21. Mr. Bright who owned 160.8 acres of land, sold 13} acres at one time and 16.004 at another time. How many acres had he left ? 22. From the sum of 13.5 and 8.7 take their difference. 23. How many tons are there in 184 tons + 16.8 tons + 661 tons + 98 tons ? MULTIPLICATION LESSON 74 1. 1 x t = id=.01; or, .1 *.1= .01. 2. u xi = 1206 = .21; or, .7 .3 = .21. 3. 18 = 1što = .027; or, .3 x .09 = .027. 4. 180 X 170 = 160 = .0056; or, .08 x .07 = .0056. 5. % * 7 = 16 = 3.5; or, .5 x 7 = 3.5. 6. Multiply 3.2 by 2.4. It will be seen from the preceding exercises that we multiply decimals like whole numbers, and point off from the right of the product as many decimal places as there are in the multiplicand and multiplier together, prefixing ciphers when the number of figures in the product does not equal the number of decimal places in both factors. Multiply : 7. 8.06 by .04 10. 1.01 by .002 13. .001 by 1.1 8. 24.38 by 1.65 11. 30.03 by 28.3 14. 41 by .001 9. .004 by 3.02 12. 161.3 by .401 15. 3.27 by .011 16. How many tons are there in 36 loads of coal, each load weighing 1.8 tons ? 17. What must be paid for 33.6 tons of coal at $ 3.75 a ton ? 18. Find the cost of 8.384 thousand feet of boards at $13.35 per thousand. DIVISION LESSON 75 OPERATION 1. Divide 1282.56 by 76.8. As the dividend is the product of the divisor 76.8)1282.56(16.7 and quotient, the number of decimal places in the 768 5145 dividend should equal the number in the divisor and quotient taken together. 4608 Since there are two decimal places in the divi 5376 dend and one in the divisor, there must be the 5376 difference between two and one, or one decimal place in the quotient. 2. Divide 136.318 by 3.185. When there is a remainder, ciphers may be annexed to the dividend and 3.185)136.3180(42.8 Ans. the division continued as shown in the 12740 operation. 8918 When the division will not terminate, 6370 and an exact quotient cannot be expressed 25480 decimally, the remainder may be ex 25480 pressed by a common fraction; or, when a number of decimal places sufficient for practical purposes has been obtained, the sign “+” may be annexed to indicate that the division is not complete. (See operations following.) OPERATION 5. 21.3615 by 3.15 11. 11.52 by .0096 6. 2.13615 by 31.5 12. 62.125 by .0007 7. 24 by .032 13. .231 by .0654 8. .819873 by 184.5 14. 6.72 by .175 9. 9.6 by .00032 15. .25 by 3.1416 10. 819.873 by 18.45 16. .0356 by .754 Find the value of: 17. 2.32 x .012 x.08 20. 62.5 : 2.5 18. 3.8 x .0225 x.5 21.' 42 :.007 19. 3.22 x 50 x.3x1 22. 126 •.63 23. 9.33 x.331 24. 1.663 = 33 25. .83} = .081 26. At $2.75 a pair, how many pairs of skates can be bought for $1100 ? 27. I paid $41.715 for 30.9 yards of carpet. How much did I pay for 1 yard ? 28. At $.374 per bushel, how many bushels of oats can be bought for $13.12; ? 29. At 38¢ a yard, how many yards of ribbon can be bought for $9671 ? 30. At the rate of 48.875 miles a day, how many days will it take a man to ride on his bicycle a distance of 281.03125 miles ? LESSON 77 1. How much will 350 celery plants cost at 30¢ a hundred ? 2. Find the cost of 36 articles at 25$, 20$, 1214, 3314, , 50%. 3. At 123¢ a pound, how many pounds of cheese can be bought for $2? 50¢ ? 621¢ ? 873¢? 4. Find .621 of 160 yards. 621% of $1.60. 5. 100 times a certain number is 425. Find the number. 6. What part of .8 is .2? What part of .8 is .08 ? 7. The multiplicand has 3 decimal places, and the multiplier has 2. How many decimal places are there in the product ? 8. What part of .4 is .25? Change .2 of a day to hours. 9. If .3 of a yard of ribbon is worth 6¢, how much is 1 yard worth ? 2.5 yards ? 10. 1 equals how many hundredths ? .1 equals how many hundredths? 2 equals how many hundredths ? 11. If 36¢ is the difference between .2 and .02 of a boy's money, how much money has he ? 12. What decimal of a day is 2 hr. ? 3 hr. ? 4 hr. ? 6 hr. ? 13. The product has 6 decimal places, and the multiplier 2. How many decimal places has the multiplicand ? 14. What part of 3.2 is .16 ? Reduce .1 of a day to hours. LESSON 78 1. If 10 tons of coal cost $10.50, how much will 7.6 tons cost ? 2. If 9.3 yd. of cloth cost $20.925, find the cost of 90.3 yd. 3. Find the sum of .163, 25.123, 81, .61, 163, 663, .663, and .621 |