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MICROCOPY RESOLUTION TEST CHART 
 
 (ANSI and ISO TEST CHART No. 2) 
 
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 1.8 
 
 J >IPPLIED IIVMGE 
 
 inc 
 
 1653 East Main Street 
 
 Rochester, New York 14609 USA 
 
 (716) 482 - 0300 - Phone 
 
 (716) 238- 5989 -Fox 
 
■- 'I' 
 
 THE WONDERS 
 
 M' 
 
 OF 
 
 AKI7HMETIC 
 
 OR 
 
 The Art of resolving, usinfr only one figure, or by 
 simple Addition, all rules of Interest or Dis- 
 count, simple or complex, without having 
 to divide, acquired in ten minutes 
 study. 
 
 STOCK OPERATIONS, 
 
 The Four Boles proved by a simple AdditioOi 
 
 as quick as thought. 
 
 BY 
 
 J. M. DANIAX7D. 
 
 fc'^S' 
 
 MONTREAL : 
 
 BUSllBE SENfiCAL, PRINTER and PUBLISHER, 
 6, 8 and 10 St. Vincent Street, 
 
 1880 
 

 Entered according to the Act of Parliament of Canada, 
 in the year one thousand eight hundred and eighty 
 m the office of the Minister of Agriculture by J. M 
 
 0«^4j^4.^8 
 
'Canada, 
 d eighty, 
 by J. M. 
 
 CHAPTER I. 
 
 Showing how all operations of Interest or Discount 
 can be made without a Division. 
 
 If you want to find the interest on any sum, for one 
 year, you shall multiply the capital by the rate, either 
 simple or complex, that is with decimal fractions. 
 
 The rate is called simple when it is not followed by 
 any fraction, as 1,2, 3, 4, 5, 6, 7, 8, 9, etc. 
 
 The rate is called complex when it is followed by 
 fractions, as 1.25, 1.75, 2.20, 2.25, 2.75, etc. 
 
 When you have multiplied the capital by a simple 
 rate, you point off two decimals, by which you have 
 divided by 1 00. The dollars stand to the left of the point 
 and the cents to the right. 
 
 If you have a complex rate, you point off four deci- 
 mals and the dollars stand to the left of the point, as 
 above, and the cents to the right. 
 
 What is the interest on $4842 at 6 o^o for one year ? 
 Example : $4842 
 
 6 o;o 
 
 $290.52 Answer: $290.52 cents. 
 What is the discount on $542 at 4 o^o for one year ? 
 Example : $542 
 
 4 0^0 
 
 $21.68 Answer : $21.68 cents. 
 What is the interest on $6424.10 at 5o?oforone 
 year? 
 
 Example: $6424.10 
 
 5 ojo 
 
 321.2050 Ans.: $321.20 cts. 50 on i. 
 What is the interest on $248 at ^ o/o for one year ? 
 Example : $248 
 
 4.50 0/0 
 
 
 992 
 
 11.1600 Answer: $11.16 cents. 
 
V 
 
 — 4 — 
 
 $23,223 
 8 
 
 0/0 
 
 1857.84 Answer: $1857.84 cents 
 
 oneVay ? '"""" °'' "''"""' "" «3«2 at i o;o for 
 , Example: $3422.00 
 •art.^, ■ ... ■ ^80221 Answer $0.38 cents 
 
 471332 
 
 21 —days 
 
 471332 
 942664 
 
 B 
 
 you 
 $9.9 
 oper 
 not 
 
 Proc 
 
 will call a«; «q Qn^l^^^? • ^"^wer : $9.89 79 that I 
 
 Prooi by Division : 
 4242 
 4 a/o 
 
 16968 
 
 21 — days 
 
 16968 
 33936 
 
 356328 I 360 
 
 3232 1 « 
 
 35':8 9.898 
 2880 
 0000 
 
 
 2r 
 
 Yc 
 
 oddi 
 Pr 
 
 Answer : 9.90 cents. 
 
 Oe 
 
— 5 — 
 
 X, can be 
 
 one after 
 1 it, begin- 
 m right to 
 each add- 
 s if every 
 
 It 4 0/0 for 
 
 Its. 
 
 il days? 
 
 79 that I 
 usandths 
 
 But as you llnd yourself with more than i cent rest, 
 yo" may add a unit to the cents and have the result : 
 $9.90 cents. This result is the same as by the other 
 operation which is much shorter and in which you do 
 not have to divide. 
 
 What is the interest on $548.10 at 4 o^o for 4 days ? 
 
 Example: 54810.00 
 6089998 
 
 4 •-days 
 
 ^ . . ^ 24.35.99.92 Answer : $0.24 cents. 
 Proof by Division : 
 
 548.10 
 
 4 0/0 
 
 219240 
 
 4— days 
 
 876960 1 360 
 1569 ' 
 
 1296 2436 
 
 2160 
 
 ^ . 0000 Answer : $0.24 cents. 
 
 2nd example : 
 
 What is the interest on $4842 at 4 o;o for one dav? 
 4842.00 ' 
 
 537998 Answer : $0.54 cents. 
 
 You strike off, as before, the thousandths, and you 
 add a unit to the cents. 
 Proof by Division: 
 • 4842 
 
 4 0/0 
 
 19368 1 
 1368 1 
 
 ooon 
 
 0000 
 
 360 
 
 CO o 
 OO.O 
 
 Answer : $0.54 cents. 
 
 5ents. 
 
 On the same capital at 4 o/o for 15 days 
 
 y 
 
 .^ 
 
— 6 — 
 
 Example: 4842.00 
 537998 
 
 15 — days 
 
 2689990 
 537998 
 
 \ 
 
 Proof by Divi^fonT' ^"^^^^ ^ ^^.07 cents. 
 4842 
 4 0/0 
 
 19368 
 15— 'days 
 
 96840 
 19368 
 
 290520 } 360 
 
 2520 I 
 
 0000 8.07 Answer: 
 
 On the same capital at 6 o;o for one dav • 
 
 Example : 4842,00 * 
 
 537998 
 268999 
 
 .07 cents. 
 
 ^ _ 806997 /.nswer 
 
 Proof by Division : 
 4842 
 6 0/0 
 
 .81 cents. 
 
 29052 J 
 2520 1 
 0000 
 
 360 
 
 80.7 Answer: $0.81 cents. 
 
 Same capita! at 6 o/o for 20 days. 
 Example : 4842.00 
 537998 
 268999 
 
 $0699? 
 
 20— jours 
 
 16.139940 Answer: $16.14 cents. 
 
 Pre 
 
 San 
 
Proof by Division : 
 
 — 7 — 
 
 4842 
 60/0 
 
 29052 
 
 20 — days 
 
 581040 
 2210 
 504 
 1440 
 Other proof by Division : 
 4842 
 20— days 
 
 96840 
 36 
 
 8 
 
 24 
 
 360 
 
 16.14 
 
 Ans. : $16.14 cents. 
 
 16.14 
 
 What is the interest on 
 
 Example : 490.00 
 
 54443 
 
 108886 
 
 45^days 
 
 544430 
 435544 
 
 Answer: |M4 cents, 
 at i 0^0 foi 45 days ? 
 
 4.899870 Answer: $4.90 cents. 
 Same capital at 5 0/0 for 120 days : 
 Example : 490.00 
 54443 
 27221 
 13610 
 5 0^0 
 
 68050 
 120— days 
 
 136100 
 68050 
 
 8.166000 Answer: $8.17 cents. 
 
~8 — 
 
 Proof by Division; 
 490 
 
 8 0/0 
 
 3920 
 45— days 
 
 Proof by Division: 
 490 
 5 
 
 19600 
 15680 
 
 2450 
 120 
 
 49000 
 2450 
 
 360 
 
 ' 176400 I 
 3240 I 
 0000 4.90 
 Answer : $4.90 cents. 
 
 Two more examples : 
 Capital ;— . 
 6848.00 
 
 IoS???~"* o?o interest for 
 380443—2 070 
 190221—1 oyo 
 
 95110— io;o 
 
 47555— i 070 
 
 23777-i 0/0 
 
 360 
 
 
 (t 
 
 (( 
 
 294000 I 
 600 I 
 
 2400 8.166 
 2400 
 240 
 Answer: 8.17 cents. 
 
 Capital : — 
 20000.00 
 one day— 2222222— 4 o70 
 
 1111111-2 070 
 
 555555-1 070 
 
 277777-1 0/0 
 
 138888 — J oJO 
 
 I' 69999— J ojo 
 
 ih^iiS^^? ^""^ represent the interest for one day on 
 the respective capitals of $6848 or 20000. ^ 
 
 „n !hl operation shows what is the result of addini? 
 ttre^Cesfn "«"' " '«"' ^' ™ny «™ "a! 
 
 '^^'ttiJ^^L'^^l 3m« Sus7?KS 
 
 flrqt- iqn99i"^T?'' "' " '^^"' ^'^ ^^ isonehaliofthe 
 T ' ,^^"''21 must represent 1 070. 
 
 In the example on 20000.00, there being only one 
 
y Division; 
 
 I 
 ) 
 J. 17 cents. 
 
 .00 
 
 i22— 4 070 
 i 11-2 0/0 
 >55— 1 o;o 
 ^77-1 (^0 
 188 — i 0/0 
 '99— i 0/0 
 
 le day on 
 
 of adding 
 *■ times as 
 
 J capital, 
 decimals 
 ied off, to 
 3 right of 
 
 up from 
 ^presents 
 . then re- 
 alfofthe 
 
 aaly one 
 
 figure, 2, you cannot do «,• mise than to write 2 
 down under the ciphers and .vuu have 2222222, for the 
 interest at 4 o/o for one day ; ! 1,1 1 1 1 1 for the interest 
 at 2 mo, and so forth. 
 
 It follows that when you have added up all the fi- 
 gures of a capital sum, as many times as there are 
 figures, and adding to the figure next following on the 
 left hand the amount carried from each addition, the 
 result will he the interest at 4 o/o for one day, one half 
 of such result will be the interest at 2 o/o, and soforth. 
 
 ffl.oiL*^®" y°^ ^^°* *^ ^'"^ o^t ^^6 interest at 4 o;o on 
 |20000 for 50 days, multiply the result of the addition 
 from right to left of 20000 by 50 days and the product 
 will give you the interest, after you have pointed off 
 six decimals, the dollars standing tc the left of the 
 pomt and the cents to the right. 
 
 Example : $20000.00 
 50 jours 2222222 4 0/0 for one day 
 
 111. 11110 Answer: $111.11 cents. 
 
 The following is the way in which this adding up of 
 the capital should be done to find out the interest at 
 4 0/0 for one day : 
 
 Suppose you have to add upthe capital 4785. You 
 begin by putting down the two necessary ciphers • then 
 you add up all the figures in the capital, one after 
 
 fi?^, 5'.,.*^^^"^ ^^^^ *° ^^^ *o '^e following figure to 
 the left, the amount carried from each addition and 
 the sum will give you the interest at 4 o/o for one day. 
 
 Example: *4785,00 
 
 531664 — 4 0/0 for one day 
 
 The sum 531664 has been obtained as follows : 5 and 
 8 are 13 and 7=20 and 4=24, 1 set down 4 and carry 
 ^ ^^i^^l^*^^ '° *^® ^' I say : 2 and 5 are 7 and 8 = 15 
 and 7=22 and 4=26, 1 set down 6 and carry 2 which 
 
 I say : 2 and 5 are 7 and 8=15 and 7=22 and 4=26 
 1 set down 6 and carry 2; 2 carried and 8 are 10 and 
 /«17 and 4=21, 1 set down 1 and carrv 2; 2 carried 
 
— 10 — 
 
 X 
 
 dW, there wSh/ .1 ««»'« only, the result for one 
 
 jnultiply th^whole t'm; 4heuevTf ZT' ^^^ " 
 than one day's interest. ^"^^^^^ yo« have more 
 
 »TOTHBR EXPLANATION OP THE ADOITION. 
 
 it .?n"ecra'X"StU°t.^f:7';£ 'i-^-P""". 
 on account of the iw„„C *'?.^* '" "'e last figure 
 
 la the same manner wLnfc'^°,"''^'°8.'''« « 
 
 body of numbers, you must eohJr.^^P''"''' '" '"« 
 the number of cvohern ft.. %?'''' ""'=* """"s 'ban 
 
 them on the left Cd siSe. ^™ "^^^ '''""""•'8 
 2o524'2!'l wUl put dodi° ^ ""'•"l-'P «■« '•""•wing: 
 
 Kt?s^s-E£S??v"^^^^^^^^^ 
 
 I add the flgi-es 2 I A I' iv k''* T^"*^ *« »Pi«al, 
 aught and clrrv I '.'.:' ^' y'"'=i'„*''^ '«■ I set down 
 
 ana -^ are 3 and 2=5 and '4-9ar,rt T'Vi ' i ' ,*=*"''««* 
 •»'' carry 1 ; , carried andYa^sUliis'aZ 
 
\ 
 
 id carry 1 ; l 
 
 res in the ca- 
 4 0/0 interest 
 .53 and some 
 
 iber of days 
 in one day. 
 ?andths must 
 on by num- 
 
 the number 
 5st, because 
 esult for one 
 ' for a consi- 
 necessary to 
 have more 
 
 TION. 
 
 the capital, 
 3 last figure 
 the capital, 
 ters in the 
 more than 
 t following 
 
 (following: 
 er the ca- 
 ?oing back 
 one of the 
 ^hich it is 
 
 the num- 
 he capital, 
 set down 
 1 2=5 and 
 
 1 canied 
 set down 
 
 2=5 and 
 
 — 11 — 
 
 il7?'fK^®*o1?,!^'V^.'^.°*^ ^*^^ *"^^*5 I ^egln again 
 with the 2 (the first figure of the capital) and 1 say: 2 
 &na I are 4, 1 set down 4 and carry aught ; as I have 
 nothing more to add for the ciphers, I set down 2 for 
 each of them and also lor the first figure of the capital. 
 
 The sum of this addition is 22249110. And if I point 
 off SIX decimals, I will have 22.24, which I will put 
 down as $22.25 cents interest for one day, leaving off 
 the thousandths unless I should multiply by the num- 
 ber of days my capital has been bearing interest. 
 
 11 1 want to find out the interest at 6 070 on this ca- 
 pital which gave me as interest at 4 070 : 22249110 I 
 shall take one half of that number, and add it up to the 
 same and that will give rae the interest at 6 070 : it 
 will then only bo necessary to multiply by the number 
 ot days stated and having pointed off six decimals, I 
 will have the $ to the left and the cents and thou- 
 sandths to the right of the point. 
 
 Example: 22249110— 4 070 
 11124555 
 
 33373665 
 
 70 — days 
 
 2336.156550 
 
 Answer: $2336.16 cents. 
 
 «io^« i«*^® }^ ^^^^ ^^y' ^^ ^^^ interest asked for 
 *i . :u 2^^^^^ ^^^ ^°°^® thousandths which are left 
 off in the final result of the operations. 
 
 It is well to strike off the thousandths, and add one 
 to the cents, (as I said before) because in the final re- 
 sult only cents need be accounted for. 
 
 The addition of the capital can be made in various 
 ways ; it can be made by putting down the capital five 
 times echellons by respecting every figure,putting down 
 fave times that representing the units, five times that 
 
 ♦u^"i:'''"i'"5 ^^''^ iciiiiis, live limes liaai representing 
 the hundredths, etc., etc. 
 
 The sum of the addition will every time represent 
 the mterest at 4 070 for one day. 
 
— 12 — 
 
 What is the interest on $845 at 4 070 for 40 days ? 
 
 Example: 845 
 
 845 
 845 
 845 
 845 
 
 9388795--4 o;o for one day 
 40— days 
 
 3.7555. iToo 
 ^ Answer : $3.75.55 i. e. $3.76 cents. 
 
 55555 
 44444 
 88888 
 
 9388795—4 070 interest for one day 
 40— days ' 
 
 same 
 
 3.75551800 
 
 Answer : $3.76 cents. 
 
 hn^if!/"'"" '' *^® '^°*® for both operations. With 
 both these methods, it is necessary to point off ei^ht 
 
 certfth: ^^T' '' '^^« *^« ^ '« tL leVan t 
 cents to the right of the point. Here is the proof of the 
 
 two proceeding rules by addition of the capTtel 
 Example; $ 845.00 
 
 ^^^fn~"i °^° ^^^ °°® ^*^y 
 
 ■IV — -uuys 
 
 3.755480 Answer : $3.76 cents. 
 
for 40 days ? 
 
 day 
 
 } of the same 
 
 )r one day 
 
 $3.76 cents. 
 
 lions. With 
 nt off eight 
 left and the 
 
 proof of the 
 pital. 
 
 '3.76 cents. 
 
 Proof by division : 
 
 — 13 — 
 
 845 
 4 0/0 
 
 3380 
 40 — days 
 
 135200 I 360 
 
 2720 ' 
 
 2000 3.75 
 
 W41.41, *!. . J^^^ Answer : $3.76 cents. 
 
 With the method of adding up the capital, the oper- 
 ations are considerably shorter ; and when you have 
 acquired the habit of adding up the capital as we have 
 just been doing, you will be able to calculate interest 
 or discount a? quick as thought. 
 
 We have seen that the operations can be made by 
 adding up all the figures of the capital in order to find 
 the inteirtst at 4 o/o for one day. We propose now to 
 show how the interest can be found for the number of 
 days the capital has been bearing interesi. If you 
 niultiply the capital by the number of days and if you 
 add up the figures of the result, in the same way as 
 above, you will have the interest for the number of 
 days given. 
 
 Example of the proceeding rules ; 
 
 •845 Proof: 845.00 
 
 40 days 93887 
 
 liiSo !!"^"y' 
 
 3.7654 Answer : $3.76 cents. 3.755480 
 
 ..,, , . , Answer : $3.76 
 
 Other example with a capital of 3.241 at 4 070 for 
 12 days : ' 
 
 3241 Proof: 
 
 12 — days 
 
 6482 
 3241 
 
 38892 addition. 
 
 4.3210 Answer : $4.32 cents. 
 
 3241.00 
 3601.10 
 
 12~days 
 
 720230 
 360110 
 
 4.321320 
 
 Answer : 4.32 
 
— 14 — 
 
 Proof bv division ; 
 
 3241 
 4 0/0 
 
 25928 
 12964 
 
 155568 I 360 
 
 1156 I 
 
 768 4.32 
 48 
 
 Answer : $4.32 cents. 
 
 the adSn multiplication takes place before 
 
 Example : 
 
 845 
 40 days 
 
 33800 
 33800 
 33800 
 33800 
 33800 
 
 3.75551800 
 Answer 
 
 $3.76 cents. 
 
 rivld «t '^r^^t'jilP!™"""' the sam'e result is ar-' 
 cessary" to point oFeieMdP^t™'^'?'-'"*' '} '^ ""^y^ "«- 
 
 * .0 th^e 4 a"„Vti.^irsrft"gh''tirtii: xr" 
 
other example 
 
 — 15 — 
 
 845 
 
 40 days 
 
 33800 
 
 00000 
 88888 
 33333 
 33333 
 
 4.32 cents. 
 
 Jr of days, four 
 1 the result, on 
 
 > foregoing re- 
 ary to addsthe 
 5s place before 
 
 result is ar- 
 s always ne- 
 ' to have the 
 the point. 
 
 3.75551800 Answer : $3.76 cents. 
 
 The result remains the same, after pointing off eight 
 decimals. 
 
 AH these rules give the interest at 4 o;o ; and when 
 the interest at 4 o/o on any capital is once arrived at, 
 it is easy to get at every rate. Take one half of 4 o/o 
 you have 2 o;o ; take one half of 2 o/o you have I o»o. 
 
 When you have the 1 op rate, you multiply by the 
 rate given and thea by the number of days ; and you 
 get the interest asked for after pointing off four deci- 
 mals, if you have not added the two ciphers. 
 
 Every time you add those two ciphers to the right 
 of the capital, you must point off six decimals. 
 
 But if the rates are complex, you must point of^two 
 more decimals in the result. 
 
 If you want to operate on any rate of interest, you 
 can do so by getting first the * o;o interest which is i 
 of the 4 070 i. e. of the sum of the addition from right 
 to left, which represents the 4 o;^o rate. 
 
 Example : 3421.00 h 5 oio for 21 days 
 380110 
 190055 
 95027 
 5 0^0 
 
 475135 
 
 21— days 
 
 475135 
 950270 
 
 9.977835 Answer : $9.98 cents. 
 
\ 
 
 — J« — 
 
 rate; takeTof'the Lsuft a^add ?,'^"^'' ^^^" ^^ '^' 
 
 as there are figuresfn u • TatfJre "^ f ^ •'"''"y *'°»es 
 
 sum and you will have th^«Tfn^^^^ 
 
 to the right of the pofnt * ^ ^^" ^^'^ ^^« ^^^^s 
 What is the intere^f on 8422 at S n-i« fn„ aq i 
 Example : 8422 cSpiiar "^^^^ ^ 
 
 48— days 
 
 67376 
 33688 
 
 404256 
 I 3 o;o 
 
 1212768-totaI. 
 , . 606384 
 
 to be added u p 303192 -^i of the total, 
 
 33.6878 Answer : 33.69 
 
 ^ Proof: 842200 
 
 935776^4 o;o 
 467888 
 
 233944— unit or i 
 3 0/0 
 
 701832 
 
 48 — days 
 
 5614656 
 2807328 
 
 33:68:78: 'a"S7s' added Ul"'.''^'''?*''' '.""^ ''°'<»>'>' 
 sandths left out. ° "■* "*'«' and the thou- 
 
'ay: multiply 
 J, then by the 
 8 many times 
 icimals in the 
 md the cents 
 
 r 48 clays ? 
 
 
 )9 
 
 liplied by 
 ■esult has 
 addition 
 um. fiirn- 
 e amount 
 the thou- 
 
 - 17 — 
 
 Other example on the same capital. 
 8422 Other example : 
 48 
 
 8422 
 48 
 
 67376 
 33688 
 
 404266 
 3 
 
 1212768 
 
 1347517 
 
 673758 
 
 33.6879 
 
 0^0 
 
 67376 
 37688 
 
 404256 
 449171 
 224585 
 112292 
 
 33.6877 
 Answer : 33.69. Answer : 33.69. 
 
 In this operation, the capital has been multiplied by 
 the number of days ; then by the rate, and the result 
 was a total sum of 1212768. This result has been added 
 up from bright to left, and the answer has been one 
 fourth of the sum of this addition. 
 Proof by division : 
 8422 
 3 0^0 
 
 25266 
 48 days 
 
 202128 
 101064 
 
 1212768 
 1327 
 2476 
 3168 
 2880 
 0000 
 
 360 
 
 33.688 
 
 Answer : 33.69. 
 The rule to be followed as to the number of decimals 
 to be pointed off is the following : For the capital, two, 
 for the simple rate, two, for the two ciphers that fol- 
 
 IffW ihf\ npnitfll iwn nnH if iVtCk Y>afo ia rtnmrAav f/\w 
 
 the decimals in the rate, two, making all told eight 
 decimals, if are combined in the operation all these 
 conditions. 
 
— 18-. 
 
 Sj^ me»thod of operattng by the unit, 
 sample. 7424 d 7.50 for 50 Jays. 
 
 7424.00 
 
 824887—4 o;o 
 
 412443—2 o!o 
 
 206221-1 0/0 or unit. 
 7.50 
 
 1031 loT" 
 1443547 
 
 154665750 
 
 50-— days 
 
 , 77.33287500 Answpr • 77 qo ..„# 
 
 We Will give two examples of that below. 
 
 What IS the interest on 743 at 5.25 for 43 days? 
 oJr"" 632300 
 
 41277 ^^2554 
 
 20638-.unit 175638-unit 
 43-days 9 ^^^ 
 
 Pro< 
 
 Oth( 
 Wh 
 
 Ans 
 
 61914 
 ^2552 
 
 887434 
 5.25- -rate 
 
 1580742 
 
 22— days 
 
 San 
 Exa 
 
 4437170 
 1774868 
 44371 rn 
 
 3161484 
 3ioi484 
 
 34.776324 
 Answer : 34.78 cents. 
 
 I 
 
 4.6590?8o. Answer : 4.66. 
 
 Ans 
 
Proof by division 
 
 — 19 — 
 
 5.25 
 
 3715 
 1486 
 3715 
 
 390075 
 
 43— days 
 
 1170225 
 1560300 
 
 77.32 cents, 
 lit, let the 
 
 )8l for one 
 by number 
 I represent 
 lapital has 
 'equired to 
 
 days? 
 
 nit 
 
 ays 
 
 .78 cents. 
 
 I 
 
 16773225 I 360 
 
 2373 I 
 
 2132 4.6592 
 3322 
 825 
 
 105 Answer : 4. 66. 
 
 Other examples : 
 
 What is the interest on 4842 at 4 ojo for one day ? 
 484200 Proof by division : 
 
 0.537998 4842 
 
 Answer : 0.54 cents. 4 o;o 
 
 19369 1360 
 
 1368 I 
 
 2880 538 
 0000 
 Answer : 0.54 cents. 
 Same capital at 4 o?o for 15 days : 
 Example : 4842.00 Proof by division : 
 
 537998 
 
 15 — days 
 
 4842 
 4 0/0 
 
 2689990 
 537998 
 
 19368 
 
 15— davs 
 
 8.069970 
 Answer : $8.07 cents. 
 
 96840 
 19368' 
 
 290520 
 
— 20 — 
 
 290520 I 360 
 2520 
 
 0000 8.07 
 Answer : $8.07 cents* 
 
 Same capital at 6 o/o for 20 days 
 
 Example: 484200 Proof by division. 
 
 0^7998 — 4 o;o '"'" 
 
 268999—2 o/o 
 
 4842 
 20 — days 
 
 806997 
 
 20— days 
 
 16.139940 
 \ Answer: $16.14 cents. 
 
 96840 I 6 
 36 I 
 
 8 16.14 
 24 
 Answer : 16.14 cents. 
 
 What is the interest on $490 at 8 o/o for 45 days? 
 Example : 490.00 
 
 54443—4 o;o 
 108886— double or 8 o;o. 
 45— days 
 
 544430 
 435544 
 
 ^ 
 
 4.899870 
 
 Answer : $4.90 cents. 
 
 Proof by division : 
 
 490 
 
 
 8 0/0 
 
 
 3920 
 
 45 — days 
 
 
 19600 
 15680 
 
 
 irromn l nnn 
 
 3240 I 
 
 0000 4.90 
 
 Answer : 4.90 cents. 
 
»20 I 360 
 
 .20' 
 
 00 8.07 
 
 r : $8.07 cents. 
 
 hy division. 
 
 20 — days 
 
 14016 
 
 I6T4 
 24 
 
 : 16.14 cents, 
 or 45 days? 
 
 0. 
 
 ats. 
 
 rs 
 
 : 4.90 cents. 
 
 — 21 — 
 
 Same capital at 5 070 for 120 days. 
 Example: 490.00 
 
 54443 
 
 13610 — unit or both together 5 0/0. 
 
 68053 
 
 120~days 
 
 1361060 
 68053 
 
 8.166360 Answer : $8.17 cents. 
 Proof by division : 490 
 
 5 o;o 
 
 2450 
 i20-~days 
 
 4900 
 2450 
 
 360 
 
 294000 
 600 
 2400 8.166 
 2400 
 
 _., , , ,^ . , 240 Answer: 8.17 cents. 
 
 What is the interest on 2333 a 5 010 for 22 days ? 
 
 Example : 
 2333.00 
 259221—4 070 
 129610—2 o;o 
 64805—1 op or unit; 
 5 0/0 
 
 324025 
 
 22— days 
 
 648050 
 648050 
 
 7.128550 
 Answer: $7.13 cents. 
 
 Proof; 
 2333 
 5 0^0 
 
 11665 
 
 22— days 
 
 23330 
 23330 
 
 256630 I 360 
 
 1030 7.128 
 3100 
 220 
 Answer: $7.13 cents. 
 
V 
 
 — 22 — 
 
 What is the interest on 745 at 7 o70 for 15 days? 
 
 Example : 
 tt)§3 ^ 745.00 
 id 5 & 82776—4 070 ' 
 ^«^ 41388-2 0/0 
 ^ 5 20694—1 o/o 
 
 144858 
 
 15 — days 
 
 724290 
 144858 
 
 5215 
 15— days 
 
 2172870 
 Answer: 2.17 cents. 
 
 Other example at 
 48948.20. 
 
 26075 
 5215 
 
 78225 
 622 
 2625 
 105 
 
 360 
 
 2.17 
 Ans. 
 
 2.17 cents. 
 0/0 for 20 days on a capital of 
 
 «50|3 48948.20.00 
 
 "" - I 543868885—4 o/o 
 271934442— 2 070 
 135967221—1 o/o 
 
 951770548 
 
 20— days 
 
 ^7i o 
 
 CO <»^ 
 
 Proof; 
 48948.20 
 
 7 0/0 
 
 34263740 
 
 20— days 
 
 190.35410960 
 Answer: 190.35 cents. 
 
 Ans. 
 
 685274800 
 3252 
 1274 
 1948 
 1480 
 400 
 $190.35 cents.— 40 
 
 360 
 
 190.3541 
 
 You may see that the result arrived at is always the 
 same as with a division, and the operation is much 
 shorter as it is easier and more convenient to add un 
 and to multiply than to divide. ^ 
 
 With this method you will save much time, because 
 you won t have the trouble to find out how many times 
 „„.. , ^^^.j.. ^jjjj ^^^^^^ you have ac- 
 
 quired the habit of adding up the capital from right to 
 left, you Will be able to do all rules of interest or dis- 
 count as quickly as you can write down the figures 
 
 
\ 
 
 >r 15 days? 
 
 17 
 
 s. : 2.17 cents. 
 
 n a capital of 
 
 roof; 
 8.20 
 7o;o 
 
 1740 
 20— days 
 
 800 I 360 
 
 190.3541 
 8 
 
 80 
 400 
 -40 
 
 is always the 
 tion is much 
 3nt to add up 
 
 Lime, because 
 V many times 
 you have ac- 
 from right to 
 erest or dis- 
 he figures. 
 
 — 23 — 
 
 RULE AT 6 o;0. 
 
 In all rules at 6 op, where the number of days is 
 divisible by 6 without leaving a fraction, the capital 
 may be multiplied by the figure obtained as quotient. 
 Example :— What is the interest on 745 at 6 o?o for 
 42 aays ? 
 
 745 745 for 12 days 
 
 7 2 
 
 1.490 
 
 5.215 
 
 Answer : 5,21 Aus. : 1.49 cents. 
 
 What is the interest on 4323 at 6 o/o for 48 days ? 
 Example: 4323 
 48 
 
 Proof: 
 
 34,584 
 4323.00 
 480332 
 240166 
 
 Answer : 34.58 
 Proof: 745.00 
 82776 
 41388 
 
 720498 
 48 
 
 5763984 
 2881992 
 
 34.583904 
 Answer: 34.58 
 Proof by division ; 
 745 
 6 0/0 
 
 4470 
 
 42 — days 
 
 8940 
 17880 
 
 124164 
 
 12— days 
 
 248328 
 124164 
 
 1.489968 
 Answer : 1.49 cents. 
 By divisor 6. 
 745 
 42— days 
 
 360 
 
 187740 
 
 774 I 
 
 540 5.21 
 180 Answer ; 
 
 1490 
 2980 
 
 
 31290 
 12 
 9 
 
 6 
 
 5.215 
 
 30 
 Answer : 5.21 cents. 
 
 5.21 
 
— 24 — 
 
 The same rule applies to the 4 o;o interest where the 
 Sw^ ^^ ^^ divisible by 9. Examples are given 
 
 It is clear that, as 42 divided by 6 gives 7, 1 multiply 
 745 by 7 and pomt off three decimals in the result in 
 order to have the $ to the left of the point and the 
 cents to the right. 
 
 What is the interest on 745 at 4 o70 for 36 davs? 
 Example: 745 ^ 
 
 4 
 
 2.980 Answer : 2.98 
 Other example at 4 o?o for 72 days on a capital of 
 3248 
 i 8 
 
 Proof by addition of 
 
 the capital : 
 
 745.00 
 
 8277b 
 
 36 — days 
 
 496656 
 248328 
 
 25 984 Answer: 25.98 
 
 Proof by division 
 745 
 4 0^0 
 
 2980 
 36 — days 
 
 2.979936 
 Answer 
 
 2.98 
 
 17880 
 8940 
 
 107280 J 
 
 3528 I 
 
 2880 
 
 0000 
 
 360 
 2.98 
 
 R«foa^o„ , u . Answer: 2.98 cents. 
 
 Rates can also be computed with the capital. 
 What is the mtorest on $840 at 6 o;o for 70 days ? 
 Example: 840— 4o70) . . ^ 
 
 420—2 op / ^^^^°fif together 6 o/o. 
 
 1260 
 
 Tn A , 
 
 88200— to be added up 
 
 9.7998 Answer : $9.80 cents. 
 
Brest where the 
 iples are given 
 
 IS 7, 1 multiply 
 n the result in 
 point and the 
 
 ir 36 days? 
 
 a capital of 
 
 f by division : 
 45 
 4 op 
 
 80 
 
 36 — days 
 
 80 
 
 
 
 30 j 360 
 
 ?0 2.98 
 
 30 
 
 2.98 cents. 
 
 ipital. 
 
 •r 70 days ? 
 
 fether 6 o/o. 
 
 — 25 — 
 Proof by putting down the capital in echellons : 
 
 Proof: 
 
 1260 
 1260 
 1260 
 1260 
 1260 
 
 13999860 
 70- 
 
 9.79990200 
 
 840.00 
 93332—4 6?n 
 46666—2 0^0 
 
 139998 
 
 70— days 
 
 -days 
 Answei ; 9.80 
 
 9.799860 
 
 Answer: 9.80 
 
 Other example at 7 o/o on a capital of 840, for the 
 same number of days : 
 
 Capital— 840— 4 o/o ) 
 
 Half— 420— 2 o?o }• Together 7 o/o 
 Quarter— 210— 1 o/o J 
 
 1470 
 70— days 
 
 Proof : 
 
 102900— to be added up 
 11.4332 Answer: 11.43 cents. 
 
 840.00 
 
 83332—4 0/0 ) 
 
 46666 — 2 070 > together 7 o70 
 23333—1 0/0 ) 
 
 163331 
 
 70— days 
 
 80 cents. 
 
 11.433170 Answer: 11.43 cents. 
 
 In the 6 o/o rule we have taken one half of 840, 
 which we have added to the latter sum ; and we have 
 multiplied the total 1260 by the number of days given, 
 the result was 88200, we have added up the figures of 
 this result as many times as there are figures in it; we 
 
— 26 — 
 
 V 
 
 have pointed off four decimals (as the two ciphers 
 ?'?QOQ"?i Jd^ied) and we have had for an answer : 
 y. /y98 that we called 9.80 leaving out the thousandths 
 and adding one to the cents. 
 
 r.„?f"' ^® ^°°,^ *^^' *h« addition can be made by 
 puttipg down the capital in echellons in the manner we 
 
 r^h^f 1. /"^S^fi?- r^^'^ '^ tantamount to adding up from 
 right to left the figures in the capital. © i' "^ 
 
 Some examples will be given here : 
 
 EXAMPLES BY ECHELLONS. 
 
 What is the interest on 840 at 7 o?o for 70 days ? 
 
 840—4 0^0 ■) 
 
 420—2 o?o (.together 7 070 
 210—1 (^oj ' 
 
 1470 
 1470 
 1470 
 1470 
 1470 
 
 16333170 
 
 70— days 
 
 01 
 
 Otl 
 
 11.43321900 Answer: 11.43 cents. 
 
 Pre 
 
 Other example : 
 
 00000 
 77777 
 44444 . 
 
 mil 
 
 Proof: 
 
 840.00 
 
 93332—4 070 
 46666-2 0/0 
 23333 — 1 0/0 
 
 16333170 
 
 70 — days 
 
 163331 
 
 70 — davs 
 
 11.43321900 
 
 Answer: 11.43 
 
 11.433170 
 Answer: 11.43 cts. 
 
V 
 
 the two ciphers 
 i for an answer : 
 i the thousandths 
 
 ;an be made by 
 in the manner we 
 ) adding up from 
 
 i. 
 
 for 70 days? 
 
 ' 7 0^0 
 
 cents. 
 
 Proof: 
 
 0.00 
 
 5332—4 0/0 
 3666 — 2 0/0 
 J333 — 1 0/0 
 
 1331 
 
 70 — days 
 
 !170 
 
 wer: 11.43 cts. 
 
 — 27 — 
 
 Other proof: 
 
 840— Capital 
 70 — days 
 
 58800— to be added up and struck off 
 65331 — 4 0/0 
 32665—2 0/0 
 16332—1 0/0 
 
 11.4328 Answer: 11.43 cents. 
 
 Other example at 8 o/o for 41 days on a capital of 
 
 42231.00 
 4692332 
 
 2— Multip. or doubling the sum 
 
 9384664 
 
 41 — days 
 
 9384664 
 37538656 
 
 384.771224 Answer: 384.771224 
 
 Proof by division: 
 
 42231 
 8 0/0 
 
 337848 
 
 41— days 
 
 337848 
 r 51392 
 
 13851768 
 3051 
 
 kill 
 
 2776 
 2568 
 
 360 
 
 
 48 Answer: 384.77 cents. 
 
— 28 — 
 
 In all these rules by putting down the capital by 
 echellons it is necessary to point off eight decimals in 
 order to have the $ to the left of the point and the 
 cents to the right. 
 
 OPERATION BY ONE FIGURE ONLY. 
 
 All operations can be made by one u^ure only 
 either with the addition or with the division. 
 What is the interest on 840 at 4 o/o for 70 days ^ 
 
 \ Example : 
 
 840 
 7— regulating figure 
 
 5880— sum to be struck off 
 6531— addition 
 1680 —double capital 
 
 23331 
 
 4 0/0 rate 
 
 93324 
 
 70 — days 
 
 6.532680 
 
 Answer : 6.53 cents. 
 
 Other example a 8 o?o on the same capital for 50 
 days. 
 
 840 
 
 7— regulating figure 
 
 5880— sum to be struck off 
 6531 — addition 
 1680 —double capital 
 
 23331— unit 
 50 — days 
 
 1166550 
 
 
 9.332400 
 
 Answer : 9.33 cents. 
 
Ihe capital by 
 
 fht decimals in 
 I point and the 
 
 FLY. 
 
 e iigure only, 
 
 sion. 
 
 3r 70 days ? 
 
 'e 
 koff 
 
 )r : 6.53 cents, 
 capital for 50 
 
 
 — 29 — 
 
 Proof by addition: 
 840 
 70 — days 
 
 58800 
 6.5331 
 
 Answer : 6.53 cents. 
 
 0/0 
 
 cents. 
 
 Proof by addition of the figures in the capital, at 8 
 
 840.00 
 
 93332 
 
 186664 
 
 50 days 
 
 9.333200 Answer : 9.33 cents. 
 Other proof : 840 
 
 50 — days 
 
 42000 
 
 4.6666—4 o;o. 
 2 
 
 9.3332—8 0/0. 
 
 Answer : 9.33 cents. 
 
 cJhe'Sil^li^T ^' r^"Ja«"g figure, because it 
 can De made use of m all operations In fart if fn». 
 
 wJj], ? ":?" ''™'=* <"f «'>'l 'h« sum of th^aZmon 
 pUa.r2 i? ^S^C^ ^S"" -«P'-«<>- of '^-■ 
 
 ine poiui auu ihe cents to the richt "" "" "' '"" "' 
 
 Otiier example on the same 
 for 82 days . • 
 
 capital of840 at 5.25 0/0 
 
— 30 — 
 
 840 
 7— regulating figure 
 
 5880— to be struck off 
 6531— addition 
 1680 —double capital. 
 
 23331— unit 
 5.25 — rate 
 
 116655 
 46662 
 116655 
 
 12248775 
 
 82-.days 
 
 24497550 
 97990200 
 
 10.04399550 
 
 Answer : 10.04 cents. 
 
 PROOF. 
 
 84000 
 
 93332—4 0/0 
 
 46666—2 0/0 
 
 23333—1 0/0 
 
 5.25 — rate 
 
 840 
 5.25 
 
 U6665 
 46666 
 116665 
 
 12249825 
 
 82— days 
 
 24499650 
 97998600 
 
 10.04485650 
 Answer : 10.04 cents. 
 
 4200 
 1680 
 4200 
 
 441000 
 
 82— days 
 
 882000 
 3528000 
 
 36162000 J 360 
 
 1620 I 
 
 180 10.04 
 Answer : 10.04 cents. 
 
— 31 — 
 
 ♦v.}T® must here point off eight decimals on account of 
 the two decimals on the rate with this method. 
 
 Ifota. — Whenever the rate is simple, six decimals 
 are pointed off, and eight decimals whenever the rate 
 IS complex. 
 
 .r.^^ *^u 5"'? ^' ,^ °/o '8 of the most frequent occur- 
 ence with traders, I will give some more examples of it. 
 
 What is the interest on 4800 at 6 o/o for 50 days ? 
 
 Example: 4800.00 
 
 533332--4 o;o 
 266666—2 o;o 
 
 799998 
 
 50— days 
 
 39,999900 Answer : $39.99. 
 
 .^^u""^ r.?^" ^*" ^^^' leaving out the thou- 
 sandths and adding one to the cents. 
 
 What is the interest on 2323 at 6 op for 16 days ? 
 
 Example : 
 232300 
 
 258110— 4 0/0 
 129050—2 0/0 
 
 387160 
 
 16— days 
 
 2322960 
 387160 
 
 Proof; 
 2323— capital. 
 16 — days 
 
 13938 
 2323 
 
 37168 — to be added up 
 41295—4 070 
 20647—2 0/0 
 
 6.194560 
 R6ponse: $6.19 cents. 
 
 R 1Q/.9 
 
 Answer : 6.19. 
 The 6 0/0 rule can be made in the following manner : 
 
— 32 — 
 
 ^^^^fn ' ^" * ^'^P^^^^ °^ ^^^ ^^'^ ^2 days. 
 
 ^fi „, Proof by division: 
 ^—0/0 840 
 
 5040-to be struck off __82-d8y8 
 
 5599--addition leso 
 
 o40 — capital 6720 
 
 13999 
 
 82 — days 
 
 27998 
 111992 
 
 68880 
 8 
 28 
 48 
 . Answer : 1 1 .48 cents. 
 
 1147918 Answer ; 11.48 cents. 
 The operation has been done this way : the canital 
 has been multiplied by 6, the result was 5040, ^this 
 
 ire fl'.urrinTt -^Z' '^^'^ "L?.?."^^"^ times as there 
 are ngures m it; the sum was 5599, under this we hnvA 
 
 put down the capital, beginning inder the te^l^^II 
 we have seen done with the regulating figure 7 with 
 this difference that this time we do not double tCca- 
 pital ; then we have multiplied hy the number of davs 
 given and we have pointed off five decimals (this is f 
 general rule for this method) ^ 
 
 The same rule by the divisor 7 is given below : 
 Example: 840 p^oof : 840 
 
 I 932—4 o;o 
 
 5880 _466-2o/o 
 
 ifi«n^ ^398 
 
 _^ 82-days 
 
 23331 
 6 o;o 
 
 139986 
 82 
 
 279972 
 1119888 
 
 •11.478752 
 
 2796 
 11184 
 
 11,4636 
 Answer: 11.46 cents. 
 
 Answer: 11.48 cents. 
 
lays. 
 
 of by division ; 
 
 840 
 
 82— deys 
 
 680 
 20 
 
 880 I 6 
 
 18 
 
 r: 11.48 cents. 
 
 y: the capital 
 as 5040, this 
 times as there 
 ' this we have 
 the tenths, as 
 Sgure 7, with 
 louble the ca- 
 imber of days 
 als (this is a 
 
 i below : 
 40 
 
 32 — 4 o;o 
 36 — 2 0/0 
 
 )8 
 
 J 2 — days 
 
 )6 
 
 (6 
 
 : 11.46 cents. 
 
 11.48 cents. 
 
 — 33 - 
 
 nn!^!!^i!^'^ kind of proof, it would be necessary to add 
 ord.r»n^'?T.f "'" "^^^'^'^" ^''^"^ '•ight to left, in 
 given befow "'""^ '^^''^^' ^^^le examples are 
 
 What is the interest on 450 at 6 o;o for 50 days ? 
 Example : 
 
 450 
 7 
 
 3150 
 3499 
 900 — double capital 
 
 12499 
 6 0/0 
 
 Proof: 
 450 
 499—4 0/0 
 
 74994 
 
 50— ^ays 
 
 3.7500 
 Answer : 3.75 cents. 
 
 3.749700 Answer : 3.75 cents. 
 
 For the modus operandi see first rule by the divi- 
 
 fo ]^^^^ F^°°^' ^J?! a,<^^ition has been made from right 
 i nin J""!? S?n ^^^^^ ' ^ ^*d i" this way 500, as the 
 LTi.f 7.n^?' ?n ^ T ^"t'^^est which gives 750 ; X 
 
 tW J^^.^y ^^^°^ ^ ha^« for an answer 3.75. 
 f«n*c ?? r?^/"^® ^^ generally unsed by accoun- 
 tants; It 18 to hud out the 6 0/0 interest for 60 days on 
 any capital, by pointing off two decimals. 
 
 What is the interest on $450 for 60 days at 6 o;o. 
 Answer : 4.50 cents. j a.* u u^u. 
 
 Proof by division : 450 
 
 60 
 
 ■li{j\j\} 
 30 
 
 I 
 
 4.500 
 
 Answer : 4.50 cents. 
 
Other proof: 
 
 — 34 — 
 
 45000 
 49999 
 24999 
 
 74998 
 60 
 
 4.499880 Answer : 4.50 cents. 
 
 What is the interest on 450 at 4 o;o for 90 days ? 
 Answer: 4.50 cents. 
 
 Proofby division : /»50 
 
 )0 
 
 40500 
 45 
 
 4.500 
 
 Answer : 4.50 cents. 
 
 This, as you may see, gives a correct answer, but 
 these two last rules, by pointing off two decimals, caii 
 only be applied to interest for 60 or 90 days. When 
 the mterest at 6 om for 60 days is found, you mav 
 easily find it for 36 days, for 15, for 7i, etc. If for more 
 than 60 days, you may add the 7i, 15, or 30 days in- 
 lerest, etc. 
 
 r.J^J}^Ju^° ^^^ ^ ^t^ ^"'^s, three decimals are 
 Pf ihi,ri^° k' ^|J*"^L*.^^P*^6^ *s left out in the divisor; 
 U should be 60 or 90 instead of 6 or 9 ; to equalize the 
 matter it should be necessary to strike off one figure in 
 the Gividend, if this has not been done, there is one 
 decimal more m the quotient, three instead of two. 
 
 It follows tbat the capital had better be multiplied 
 
 «y.?!>"S???.«!: S^ .^^.y^ and divided by 6, if it is at 
 V -„Yu, \ji uiviuuu vy y, 11 it ia ^i 4 o«q^ 
 
 This last method may be applied to any number of 
 
— 35 — 
 
 : 4.50 cents. 
 30 days ? 
 
 
 
 : 4.50 cents. 
 
 nswer, but 
 cimals, cari 
 lys. When 
 , you may 
 If for more 
 30 days in- 
 
 icimals are 
 -he divisor ; 
 qualize the 
 le figure in 
 here is one 
 of two. 
 
 multiplied 
 6, if it is at 
 
 number of 
 
 BULE FOR MAKING ALL OPERATIONS WITH THE 
 DIVISOR 9. 
 
 What is the interest on $840 at 3 o;o for 50 days ? 
 Example: 840 Proof: 31500 
 
 3 0/0 3.4999 
 
 Answer : 3.50 cents. 
 
 2520 
 
 50 — days 
 
 total.— 126000 
 half.— 63000 
 quarter.— 31500 I 9 
 
 45 I 
 
 3.500 Answer : 3.50 cents. 
 
 OTHER PROOF. 
 
 84000 840 
 
 93332 3 070 
 
 46666 ' 
 
 23333 2520 
 
 3 0/0 50— days 
 
 69999 
 
 50 — days 
 
 126000 
 
 1800 
 
 0000 
 
 3.499950 
 Answer : 3.50 cents. Answer : 3.50 cents. 
 
 In these operations with the divisor 9, the result of 
 the multiplication by the rate and by the number of 
 days, should be divided first by 4 and then by 9. 
 
 Remark.— The addition of the capital from right to 
 left, as we have previously done, is equal to the nine- 
 tieth part; if this ninetieth part is divided by four, we 
 have the three hundred and sixtieth part, or the unit, 
 or the interest for one day. 
 
 If we should multiply the capital by the number of 
 days before dividing by 9, we will have as quotient 
 the interest at 4 o?o, for the number of davs the cauital 
 has been multiplied by. 
 
 If the capital is divided before the multiplication by 
 the number of days, we shall follow the division up to 
 three decimals ; and after the multiplication by the 
 
— 36 — 
 
 number of days, we shall point 
 der to have the $ to the left and 
 of the point. 
 
 What is the interest on 450 at 
 Example : 450 
 
 50 
 
 22500 
 45 
 Answer : 2.50. 
 
 2.500 
 
 What is the interest on 5555 a 
 Example : 5555 
 
 80 
 
 Answer : 
 
 5555 
 80 
 
 444400 
 84 
 34 
 70 
 70 
 7 
 49.38 cents 
 
 off six decimals in or- 
 the cents to the right 
 
 4 070 for 50 days ? 
 Proof : 45000 
 49999 
 50 
 
 2.499950 
 Answer : 2.50 cents. 
 
 4 0/0 for 80 days ? 
 Proof : 555500 
 
 617220 
 80 
 
 49.377 
 
 49377600 
 Answer : 49.38 cts. 
 
 444400 
 49.3776 
 Answer : 49.38 cents. 
 
 Proof by addition. 
 5555 
 5555 
 5555 
 5555 
 5555 
 
 61721605 
 80 
 
 Answer : 49.38 cents.— 49.37728400 
 What is the interest on 752 at 4 ojo for 50 davs ? 
 
 "^^^ 50 83554 
 
 50 
 
 37600 
 
 4.1776 
 
 Answer : 4.18, 
 
 
 50 
 
 I 
 
 16 > - — 4.177700 
 70 4.177 Ans. 4.18 cts. 
 70 Ans. 4.18. 
 
nmals in on- 
 to the right 
 
 )0 days ? 
 45000 
 49999 
 ' 50 
 
 2.499950 
 2.50 cents. 
 
 iO days ? 
 555500 
 617220 
 80 
 
 49 377600 
 : 49.38 cts. 
 
 
 — 37 — 
 
 It will be seen from the proofs we have made of the 
 proceeding rules, that the addition from right to left, 
 is equivalent to division by 9. 
 
 Everybody knows that the general rule is to com- 
 
 Eute interest for a certain number of days ; it is only 
 y exception that it is computed for a month or for i, 
 i or I of a year. 
 
 It is therefore necessary to use a division in order 
 to make all operations of interest or discount. 
 
 With this system, division is abolished, and advan- 
 tageously replaced by the addition from right to left ; 
 it is always easier and more convenient to add up than 
 to divide. 
 
 CHAPTER II. 
 
 iddition. 
 555 
 55 
 5 
 
 605 
 80 
 
 iOO 
 days? 
 
 addition. 
 
 00 
 
 54 
 
 50 
 
 00 
 4.18 cts. 
 
 RULES FOR THE STOCK OPERATIONS MOST IN USE. 
 
 If the 5 o;o bonds are at $75, what capital may 
 be necessary to acquire an income of $650 ? 
 
 Example: 
 
 6500 
 9100 
 
 9750,0 Answer: 9750. 
 
 This operation is done by doubling the income 
 
 xirartiaA nnA «V.^» -^..itl-^i..: i jt. _ "...-^ 
 
 '"Ir"-'" ■=■■"■- liSwii !iiui;ip:jr'i:;j^ i?y iiio tjUulSuuti. 
 
 One decimal is pointed off in the result, which is di- 
 viding by ten, and the $ stand to the left and the cents 
 to the right of the point. 
 
 2 
 
— 38 — 
 
 Proof by the rule of three. 
 Example : 5 : 75 : : 650 
 
 75 
 
 X 
 
 3250 
 4550 
 
 48750 
 37 
 25 
 
 Ai 
 
 9750 
 
 Answer: 9750. 
 
 In this operation, the 650 income has been muItiDlied 
 by the quotation, 75, and the result divided by 5 this 
 means that as $5 is the income derived from '$75 
 what capital is the $650 to be derived from ? ' 
 
 Tho above operation is made by the rule of three 
 simple, and it reads thus : 
 
 5 is to 75 as 650 is to X. 
 
 We will now reverse the preceeding rule and ask : 
 11 7.-? give 5 per cent, income, how much will 9750 giv e? 
 Example : 75 : 5 : : 9750 : X 
 
 5 
 
 48750 I 75 
 
 375 I 
 
 000 
 
 650 ; 
 
 Tf -re • ij o ,. Answer: $650. 
 
 U 75 yields 8, how much will 5625 yield ? 
 
 Example : 75 : 8 ; : 5625 : X 
 
 8 
 
 45000 I 75 
 000 ' 
 
 8 : 75 : : 600 : X 
 75 
 
 Snnn 
 4200 
 
 45000 
 
 600 Ans. : 600. 
 
 To 
 
 thef 
 sum 
 only 
 ber. 
 add 
 dowi 
 ^adde 
 whin 
 up ai 
 of al 
 must 
 
 
— 39 — 
 
 : 9750. 
 
 lultiplied 
 >y 5 ; this 
 'om $75, 
 
 ! of three 
 
 md ask : 
 ^50 giv e? 
 
 1650. 
 
 ;oo. 
 
 / 
 
 45000' 8 
 50 I 
 
 20 5625 
 40 
 00 Answer: 5625. 
 
 PROOF OF THE FOUR RULES. 
 
 Addition: 324—9 Subtraction; 84216—3 
 
 632—2 
 784—1 
 
 1740—3—3 
 
 Multiplication : 432—9 
 
 17—8 
 
 32214 
 
 52002—3 
 
 3024—9 
 432 
 
 7344—9 
 
 Division =.3 =4787 I 34 = 7 
 
 138 I «. =3 
 
 4787 270 14079=3 
 
 14 320 
 
 14 
 
 4773 
 
 PROOFS EXPLAINED. 
 
 To prove the addition, it is necessary to add up all 
 the figures of every number once, and reduce each 
 sum to one figure. The first number gives 9, as 9 is 
 only one figure, we will put it down opposite the num- 
 ber. The second number is 632, which gives 11 : we 
 add up tbis two figures and have 2, which we put 
 down opposite The third number is 784, the figures 
 added up give 19, we reduce to one figure and have 1, 
 ■' "•-• i--«.-- Yi-Fvciw. iug inree uKures », ",c. i add 
 
 up and reduced 
 
 of all the figures 
 
 roust also give the figure 3 
 
 „_, , .-, - added 
 
 to one figure give 3. And the addition 
 
 in the sum, after reducing to one, 
 
 y 
 
— 40 — 
 
 This proof may also be made by adding up the 
 figures of every number as if they were written in one 
 horizoi^tal line and forming but one number, passing 
 over the figure 9 whenever it is found and reducing 
 the sum to one figure. 
 
 The proof of the subtraction is made by adding up 
 the minuend and reducing to one figure, as for addi- 
 rion, we have therefore 21, which reduced to one 
 figure, gives 3. Then the subtrahend is added up with 
 the remai-'^er and we find again 21 which reduced to 
 one figure, .daves again the same figure 3, the figure 
 being tljie same the operation is proved to be correct. 
 
 In the multiplication, the multiplicand 432 is added 
 up and gives 9, which is only one figure and needs no 
 reducing ; the multiplier is also added up and gives 8, 
 I multiply by 8 and I have 72, I reduce lo one figure 
 and I have 9. The result of the multiplication is then 
 added up and gives 18, which reduced to one figure 
 gives 9, the two figures being equal, the operation is 
 proved to be correct. 
 
 In the division, the dividend is added up and if 
 there is a remainder it is deducted from the dividend. 
 
 Example 4787, the remainder 14 deducted, we have 
 4773, add up once every figure in the latter number, 
 you have 21, reduce to one figure, you have 3. Add 
 up the divisor 34, you have 7, add up also the quo- 
 tient 14079, you have 21, reduce to one figure, you 
 have 3, multiply 7 by 3, you have 21, which reduced 
 to one figure, gives 3. 
 
 The figure given by the dividend being the same as 
 the one given by the multiplication of the two others 
 numbers, the operation is correct. 
 
 It is not necessary to divide the sum of additions 
 by divisor 9, to prove an addition : all thai is wanted 
 is to reduce to one figure, that being equivalent to the 
 remainder after a division by number 9. 
 
 Example : add up every figures of 789654, you 
 have 39, reduce to one figure, you have 3. 
 
 1 
 2 
 3 
 4 
 5 
 6 
 7 
 8 
 9 
 10 
 
g up the 
 en in one 
 ', passing 
 reducing 
 
 riding up 
 i for addi- 
 1 to one 
 \ up with 
 iduced to 
 he figure 
 correct. 
 
 is added 
 needs no 
 1 gives 8, 
 ne figure 
 n is then 
 le figure 
 ration is 
 
 p and if 
 lividend. 
 
 we have 
 number, 
 3. Add 
 the quo- 
 :ure, you 
 reduced 
 
 same as 
 others 
 
 iddilions 
 J wanted 
 nt to the 
 
 354, you 
 
 — 41 — 
 
 By division, if vou divide 39 by 9, you have 4 • 4 
 limes 9 is 36, which deducted from 39, leaves 3. 
 
 Thus, without division, the same result is arrived at, 
 and operations can be proved as quick as thought. 
 
 In adding up, the figure 9 may be passed over ; that 
 IS to say, it is not necessary to add it up with the other 
 figures. 
 
 Multiplication Table. 
 
 2... 3... 4... 5... 6... 7... 8... 9... 10 
 
 4... 6... 8. - 10... 12... 14... 16... 18... 20 
 
 6... 9... 12... 15... fS... 21... 24... 27... 30 
 
 8... 12... 16... 20... '..... 28... 32.. 36... 40 
 
 10... 15... 20... 25... 30... 35... 40... 45... 50 
 
 12... 18... 24... 30... 36... 42... 48... 54... 60 
 
 14... 21... 28... 35... 42... 49... 56... 63... 70 
 
 16... 24... 32... 40... 48... 56... 64 .. 72... 80 
 
 .n I i?- ^^- ^^- ^^'" 5^- «3... 72... 81... 90 
 
 10 1 20... 35... 40... 50... 60... 70... 80... 90... 100 
 
 1 
 2 
 3 
 4 
 5 
 6 
 7 
 8 
 9 
 
 At 4 0/0 Multiply the capital by the number of days, 
 add up from right to left and point oflTfour decimals. 
 
 At 5 010 Multiply the capital by the number of days 
 add up from right to left, add one fourth. 
 
 At 6 0/0 Multiply the capital by the number of days 
 add up from right to left, add one half. 
 
 At 7o;o Multiply the capital by the number of days, 
 add up from right to left, add onne half and one fourth. 
 
 At 8 0/0 Multiply the capital by the number of days, 
 ade up from right to left, multiply by 2. 
 
 At 9 0/0 Multiply the capital by the number of davs. 
 add up from right to left, multiply by 2, add the 
 
 At 10 0/0 Multiply the capital by the number of 
 days, add up from right to left, multiply by 2, add one 
 
— 42 — 
 
 Ex.— 250— -4 0/0 
 30- -days 
 
 7500 
 0,8332 
 
 At 5 o;o--250 
 30 
 
 At 7 o;o— 250 
 30 
 
 7500 
 8332 
 4166 
 2083 
 
 7500 
 8332 
 2083 
 
 10415 
 
 At 6 0/0— 250 
 30 
 
 7500 
 8332 
 4166 
 
 12498 
 
 14581 
 
 At 8 o;o— 250 
 30 
 
 7500 
 8332 
 
 At 9 0/0 --250 
 30 
 
 7500 
 
 8332 
 
 16664 
 
 2083 
 
 18747 
 
 Table of numbers represewting the rates. 
 hJ^ilT^ multiply the numbers representing the rat^^ 
 tin finW?KP'^-*l ^"^ ^^^'" l>y the UmJt)ero^f days von 
 
 If you want to find out interest at 9Z «-•« toi^^ .i. 
 number 5556, to wdich add 94 qn in J ^?' !^^® ^^® 
 
 and you^have the mtereV^'aS '"''" '^'"'"""^ 
 
— 43 — 
 
 1 
 
 Hates. 
 i 0/0. 
 i o;o. 
 i 0/0. 
 i 0/0. 
 
 3 0/0. 
 
 I 0/0. 
 
 ' 0/0. 
 
 0/0. 
 
 H 0/0. , 
 H 0/0., 
 
 II 0/0.. 
 
 2 0/0.. 
 2io/o.. 
 2J 0/0.. 
 2| 0/0.. 
 
 3 0/0.. 
 
 31 0/0.. 
 3i 0/0... 
 3i 0/0... 
 
 4 0/0... 
 
 H 0/0... 
 4i 0/0. . 
 
 The SIGN 0/0 means per cent. 
 
 numbers. 
 .... Ul 
 
 1041 
 
 694 
 
 1389 
 
 ..... jHfoO 
 
 2430 
 
 1736 
 
 2778 
 
 3472 
 
 4166 
 
 .... 4861 
 .... 5556 
 .... 6250 
 .... 6944 
 .... 7639 
 .... 8333 
 .... 9028 
 .... 972'> 
 ...10416 
 ...lllll 
 ...11805 
 ...12500 
 
 Hates. 
 43 0/0. 
 
 5 0/0, 
 51 0/0. 
 
 H 010. 
 
 H 0,0. 
 
 6 0/0. 
 61 0/0. 
 6i •JO.. 
 63 0/0., 
 
 7 0/0 .. 
 71 0/0.. 
 7i 0/0.. 
 
 0/0.. 
 0/0... 
 0/0... 
 0/0.. 
 0/0 .., 
 0/0... 
 0/0 ... 
 0/0 
 
 71 
 
 8 
 
 81 
 
 Si 
 
 81 
 o 
 
 H 
 9i 
 
 91 0/0. 
 
 numbers. 
 
 13194 
 
 13889 
 
 14583 
 
 15277 
 
 15972 
 
 16667 
 
 17361 
 
 18055 
 
 18750 
 
 19444 
 
 .....20139 
 
 ....20833 
 
 ....21528 
 
 ....22222 
 
 .. 22916 
 
 ....23611 
 
 ....24305 
 
 ...25000 
 
 ....25694 
 
 .. 26388 
 
 ...27083