Place 5 opposite 1: now 1 is opposite 2=1, the answer. TO MULTIPLY ONE FRACTION BY ANOTHER. Rule.-Reduce one to decimals: then place the numerator of the other opposite the denominator : then opposite the decimal is the answer in decimals, which, if desired, can be reduced to a vulgar fraction by the preceding rules. TO REDUCE THE DIFFERENT CURRENCIES TO FEDERAL MONEY. Rule.- Place the 1 on the circular, opposite the number of shillings and parts of a shilling composing a dollar of the currency to be reduced: then, opposite the given number of shillings is the answer. Example.--Reduce 5 shillings, New York currency, to Federal money. Place 1 (on the circular) opposite 8: then opposite 5 shillings, is .625, the answer. In 15 shillings, how much? Place 1 (on the circular) opposite 4:5: then opposite 32, is $7.11, the answer. In 9 shillings, how much ? INTEREST. TO COMPUTE INTEREST FOR YEARS. RULE.Place the rate per cent. found on the cir cular, opposite 1: then opposite the principal is the interest. Example. What is the interest of $50 at 7 per cent. ? Place 7 opposite 1: then opposite 50 is $3-50, the answer. What is the interest on $40 at 64 per cent. ? Place 6.5 opposite 1: then opposite 40 is $2.60, the answer. TO COMPUTE INTEREST FOR MONTHS. RULE.—Place the principal, (found on the circular,) opposite the gauge point for months at the given per cent. : then opposite the given number of months is the answer. Example. What is the interest on $50 for three months at 7 per cent. ? Place 50, (found on the circular,) opposite 1714, (the gauge point for months at 7 per cent.,) then opposite 3 months is •875, the answer. What is the interest on $60. for eight months at 6 per cent ? Place 60 opposite -2, (the gauge point for months at 6 per cent.,) then opposite 8 months is $2:40, the answer. TO COMPUTE INTEREST FOR DAYS. Rule.-Place the principal, (found on the circular,) opposite the gauge point for days at the given per cent.: then opposite the number of days is the answer. Example.- What is the interest on $55 for 15 days at 6 per cent? Place 55 opposite 600, (the gauge point for days at 6 per cent.,) then opposite 15 days is .13 3-4. The PRINCIPAL AND INTEREST BEING GIVEN, TO FIND THE RATE PER CENT. RULE FOR ONE YEAR.—Place the interest opposite the principal : then opposite 1 is the rate per cent. Example.-Received $7.00 for the use of $50.00 for one year; what was the rate per cent. ? Place 7 opposite 50 : then opposite 1 is 14, the answer, 14 per cent. Gave $4:00 for the use of $80.00 one year: whatwas the rate per cent. ? Place 4 opposite 80: then opposite 1 is 5, the answer, 5 per cent. RULE FOR MONTHS.--Place the given interest opposite the given number of months: then observe the number opposite 12. Now place this number opposite the principal: then opposite 1 is the rate per cent. Example.—Paid 25 cents for the use of $5.00 for 4 months : what was the rate per cent. ? Place 25 opposite 4: then opposite 12 is 75. Now place 75 opposite $5.00: then opposite 1 is 15, (15 per cent.,) the answer. Gave 14 cents for the use of $60.00 one month : what was the per cent. ? Place 14 opposite 1: then opposite 12 is 1.68Now place 1.68 opposite 60: then opposite 1 is 2:8, (2% per cent.,) the answer. RULE FOR DAYS.—Place the given interest opposite the given number of days: then observe the interest opposite 365 (the number of days in a year). Place this opposite the principal: then opposite 1 is the rate per cent. Example.-Paid 14 cents for the use of $64.00 29 days: what was the rate per cent. ? Place 14 opposite 29: now opposite 365 is $1.76. Now place 1.76 opposite 64: then opposite 1 is 2.75, (27 per cent.,) the answer. Paid 23 cents for the use of $50.00, 21 days: what was the rate per cent. ? Place 23 opposite 21: now opposite 365 is 4. Place 4 opposite 50: then opposite 1 is 8 per cent., the answer THE RATE PER CENT. AND THE INTEREST BEING GIVEN, TO FIND THE PRINCIPAL. RULE FOR ONE YEAR.–Place the per cent. opposite 1: then opposite the interest is the principal. Example.--At 7 per cent. I paid $3.50 for the use of money 1 year: what was the principal ? Place 7 opposite 1: then opposite 3.50 is $50.00, the answer. RULE FOR MONTHS.- Place the interest opposite the given number of months: then opposite the point of the given per cent., for months, is the answer. Example.- Gave $2.00 at 7 per cent. for three months: what was the principal ? Place 2 opposite 3: then opposite 1.714 is $114:30, the answer. RULE FOR DAYS.- Place the given interest opposite the given number of days: then opposite the gauge point for days stands the principal. Example.- At 7 per cent., gave 15 cents for 20 days: what was the principal ? Place 15 opposite 20: then opposite 521 (the gauge point for days at 17 per cent.) is $39.00, the answer. |