Everyday Use of Subtraction 1. Mary's mother had 49 hens. She sold 24 of them today. How many has she now? 2. Don had a dime and spent 4 cents for an orange. How many cents did he have left? 3. Mr. Miller picked 109 watermelons. He saved 11 of these for a watermelon party, and sold the rest. How many did he sell? 4. There are 29 pupils in our room. 12 are boys. How many are girls? 5. Out of 99 children in our school, 15 were absent today. How many were present? 6. Jane bought a pencil for 6 cents, and gave the storekeeper 10 cents. How many cents should he give her in change? 7. Our milkman charges us 19 cents for a quart bottle of milk, but later gives us 5 cents for the empty bottle. How much does the milk alone cost us? 8. If a farmer took 69 cabbages to market and sold all except 15 of them, how many did he sell? 9. The boys in our school played against the girls in a batball game. The boys scored 18 runs, and the girls made 9 runs less than the boys. How many runs did the girls make? Make up and finish subtraction problems about 19 marbles - 16 marbles; about 39 apples - 17 apples; 16 boys 8 boys; 249 school children 129 school children. When we say "Four 5's are 20," or "4 times 5 equals 20," we multiply. Which is shorter, to add 5 +5 +5 + 5, or to multiply 4 times 5? Multiplication is a short way of adding equal numbers. 4 X 5 = 20. (c) A short way of writing "four 5's are 20" is (This is read "4 times 5 equals 20.") stands for times and means multiply. stands for equals. The sign The sign = So the multiplication table for 5 may be written : (d) How fast can you spin this wheel? Multiply the number 5 in the center by each number outside the circle. Say, "Two 5's are 10,” and so on. (e) Add these columns: X5 2 2 2 2 2| Complete this table like the one on page 25: 2. 24 4 1 7 10 9 × 5 × 5 5 5 5 5 5 5 5 5 5 5 X 2 X 7 X 1 × 3 × 6 × 5 × 4 × 9 × 8 × 10 3. If one orange costs 5 cents, how much will 4 oranges cost? 2 oranges? 7 oranges? 9 oranges? 4. A toy that costs 6 nickels costs cents. 5. John gets 10 cents for cleaning the snow from one sidewalk. One Saturday he cleaned 5 sidewalks. How much did he earn? Multiplication with 2 (a) Count by 2's to 20. 22/4 (b) Write columns of 2's on the board: 2 and so on. 2 2 2 6 Say, "Two 2's are 4, three 2's are 6," and so on. The multiplication table for 2 is as follows: |