Page 85 - Start Up Mathematics_3
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Division as Repeated Subtraction
Example 3: There are 12 ice cubes in a tray. 2 ice cubes have to be put in each
glass. How many glasses are needed?
Solution:
Put 2 ice cubes in the first glass. 12 – 2 = 10
Put 2 ice cubes in the second glass. 10 – 2 = 8
Put 2 ice cubes in the third glass. 8 – 2 = 6
Put 2 ice cubes in the fourth glass. 6 – 2 = 4
Put 2 ice cubes in the fifth glass. 4 – 2 = 2
Put 2 ice cubes in the sixth glass. 2 – 2 = 0
No more ice cubes are left. Thus, we distributed 12 ice cubes in this
way:
12 – 2 – 2 – 2 – 2 – 2 – 2
Or, we can say that we subtracted 2 six times from 12. Therefore, we
can say that division is repeated subtraction.
Thus, 12 ÷ 2 = 6.
So, we need 6 glasses.
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