1. Dividing Decimals 3-3

2. When you divide two numbers, you can multiply both numbers by the same power of ten without changing the final answer. Multiply both 0.6 and 0.3 by 10: 0.6 · 10 = 6and0.3 · 10 = 3 0.6 ÷ 0.3 = 2 and6 ÷ 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.

3. Divide. Additional Example 1A: Dividing Decimals by Decimals 8.28 ÷ 4.6 ) 82.8 46 1. 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

4. Divide. Additional Example 1B: Dividing Decimals by Decimals 18.48 ÷ (–1.75) 18.48 ÷ (–1.75) =1848 ÷ 175Multiply both numbers by 100 to make the divisor an integer. ) 175 1848. 00 Use zeros as placeholders Divide as with whole numbers. 1 –175 98 0 0.5 –87 5 10 50 –10 50 0 18.48 ÷ (–1.75) = –10.56 6 The signs are different.

5. 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. ) 125 400.0.0 Use zero as a placeholder. 3 –375 25 0 –25 0 0 Divide as with whole numbers. Estimate 4 ÷ 1 = 4 The answer is reasonable.. 2

6. 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) ) 25 240 9 – 225 15.. 0 0 6 – 15 0 0 Estimate –24 ÷ (–3) = 8 The answer is reasonable. Divide as with whole numbers.