Dividing Decimals 3-3. When you divide two numbers, you can multiply both numbers by the same power...
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Transcript of Dividing Decimals 3-3. When you divide two numbers, you can multiply both numbers by the same power...
Dividing Decimals
3-3
*Notes 7
When you divide two numbers, you can multiply both numbers by the same power of ten withoutchanging the final answer.
Multiply both 0.6 and 0.3 by 10:
0.6 · 10 = 6 and 0.3 · 10 = 3
0.6 ÷ 0.3 = 2 and 6 ÷ 3 = 2
By multiplying both numbers by the same power of ten, you can make the divisor an integer. Dividing by an integer is much easier than dividing by a decimal.
Divide.
Additional Example 1A: Dividing Decimals by Decimals
8.28 ÷ 4.6
) 82.8461.
46–36 8
–36 8
Multiply both numbers by 10 to make the divisor an integer.
Divide as with whole numbers.
0
Multiply both numbers by the least power of ten that will make the divisor an integer.
Helpful Hint
8.28 ÷ 4.6
8
= 82.8 ÷ 46
Divide.
Additional Example 1B: Dividing Decimals by Decimals
18.48 ÷ (–1.75)
18.48 ÷ (–1.75) = 1848 ÷ 175 Multiply both numbers by 100 to make the divisor an integer.
)175 1848 . 00 Use zeros as placeholdersDivide as with whole numbers.
1
–17598 0
0.5
–87 510 50
–10 50
0
18.48 ÷ (–1.75) = –10.56
6
The signs are different.
Divide. Estimate to check whether each answer is reasonable.
Additional Example 2A: Dividing Integers by Decimals
4 ÷ 1.25
4.00 ÷ 1.25 = 400 ÷ 125 Multiply both numbers by 100.
)125 400 .0 Use zero as a placeholder.3
–37525 0
–25 0
0
Divide as with whole numbers.
Estimate4 ÷ 1 = 4 The answer is reasonable.
. 2
Divide. Estimate to check whether each answer is Reasonable.
Additional Example 2B: Dividing Integers by Decimals
–24 ÷ (–2.5)
–24.0 ÷ (–2.5) = Multiply both numbers by 10.–240 ÷ (–25)
)25 2409
– 22515
.
.0
0
6
– 15 00
Estimate–24 ÷ (–3) = 8 The answer is reasonable.
Divide as with whole numbers.