40. A Number Game By using the following drill you will learn to use the multiplication tables rapidly. Multiply the number at the center 5 by the numbers around the rim. Then reverse, multiplying the numbers around the rim by the number at the center. 41. Dividing by Two 1. How many 2-cent stamps can you buy for a dime? 2. How many quarts of milk are there in 18 pints? 3. Tell how many 2-cent pencils you can buy for: 4. Count by 2's from 2 to 24; from 24 to 2. 5. Answer these questions: 4¢ 40¢ 6. Answer this question: 18÷2=? 7. The division of 18 by 2 may be shown in this way: 2)18 Your teacher will read these to you slowly. Write the answers only. 1. How many 2-cent stamps can be bought for 16 cents? For 20 cents? For 50 cents? 2. John sent 8 letters. He put a 2-cent stamp on each envelope. How much did the stamps cost? 3. At 7¢ a pint, how much will a quart of B milk cost? 4. If a quart of A milk costs 16 cents, what is the cost of a pint? 5. At 6 cents each, how much will 2 street-car tickets cost? 6. At 2¢ each, 16¢ will buy how many pears? 7. At $2 a yard, how much will 9 yards of cloth cost? 12 yards? 8 yards? 7 yards? 8. Which is the greater, 4 times 2 or 2 times 4? 43. The Meaning of One Half 1. Into how many equal parts has the apple been divided? The circle? What is each part called? 2. Into how many equal parts have the six marbles been divided? What is each part called? 0001000 One half of 6 marbles= marbles. When we divide anything into two equal parts, we call each part one half. It is written 12. 3. Kate bought 1⁄2 of a yard of 20-cent lace. How much did she pay for it? 4. William had 18 marbles and gave away 12 of them. How many did he give away? 5. John gave his sister 11⁄2 of his 24 marbles. How many did she get? 6. Peaches sell for 40¢ a dozen. What will 1/2 dozen cost? 7. Find the cost of 1/2 yard of: Lace @ 12¢, 18, 20, 14é. Ribbon @ 10, 40¢, 60¢, 16¢. 44. Buying at a Store-Multiplication I. One pound of raisins costs 14 cents. How much Find the cost of each of the following purchases: Two boxes of crackers at 13¢ a box. Two boxes of starch at 24¢ a box. II. One way of proving multiplication is by adding. In the example 2X32, we work and prove as follows: Worked by multiplication Proved by addition When we add, we find the sum. When we multiply, we find the product. 45. Working in Father's Store William helps his father on Saturdays. One Saturday he sold two pounds of apricots at 28 cents a pound. What did they bring? This is how William learned to do the work: $.28 2×8 2 $.56 16. Write the 6 under the 2. Remember the 1. 2X2=4. Add the 1: 4+1=5. Write the 5 under the 2. Put the decimal point and the dollar sign before the 5. The product is $.56 or 56¢. 1. William sold the following items also. Find the amount due from each sale: Two pounds of nuts at 29 cents a pound. Three pounds of candy at 27 cents a pound. Another Saturday, William sold three chickens at 59¢ each. How much did they bring? $.59 3X9=27. Write the 7. $1.77 Remember the 2. 15+2=17. Write 17. Put the decimal point before 7, just under the decimal point above. Place the dollar sign. 2. Find the cost of: Two dolls at 98¢ each. Two balls at 55¢ each. Two pairs of gloves at 87¢ a pair. Two dozen oranges at 39¢ a dozen. Two pounds of butter at 49¢ a pound. After working several days William learned to do these problems without using a pencil. For example, in selling 2 chickens at 58¢ each, he said this: 2X50¢ $1.00 2X8¢ = .16 $1.16 Work your examples in this way, without using a pencil. 46. The Multiplication Table of Threes You have already built the table of threes (see page 43). Study the one given on the next page. |