40
Section 1 Whole Numbers
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Using division, this problem can be solved much faster and with fewer steps.
84 ÷ 7 = 12
This division problem can be expressed in multiple ways:
• 84 divided by 7 equals 12.
• There are 12 7s in 84.
• 12 goes into 84 7 times.
• 7 divides into 84 12 times.
Example 5-1
Division is useful in determining quantities of materials or performing estimates.
A carpenter uses division to determine how many sheets of subfl oor to buy to
cover a 40′ × 36′ fl oor system.
36′
40′
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Multiply the length of the fl oor system by the width to determine the area:
40′ × 36′ = 1,440 sq ft
Divide the total by 32 since 1 sheet will cover 32 sq ft:
1,440 sq ft ÷ 32 sq ft/sheet = 45 sheets
Example 5-2
How many pieces of 8′ base trim would be needed to cover a 40′ × 36′ room?
Determine the perimeter of the room:
40′ + 40′ + 36′ + 36′ = 152′
Divide the perimeter by 8, since each piece of trim measures 8′ long.
152′ ÷ 8′/piece = 19 pieces of trim