1. 3-3 Dividing Decimals Do Now Multiply. 1.24.5  7 2. 5.4  -6.2 3. (-19.21)  (–2.1) 171.5 -33.48 40.341

2. 3-3 Dividing Decimals Learn to divide decimals.

3. 3-3 Dividing Decimals In order to divide BY a decimal, the decimal divisor must be changed into an integer. To change a decimal divisor, move the decimal point all the way to the right, noting how many places you had to move it (what you are really doing is repeatedly multiplying by 10). Now, change the dividend by moving the decimal point the same number of times. THE DIVIDEND MAY STILL BE A DECIMAL NUMBER.

4. 3-3 Dividing Decimals The rules regarding negative decimals is the same as with integers: Both signs same – quotient is positive One positive and one negative – quotient is negative

5. 3-3 Dividing Decimals Divide. Example A 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

6. 3-3 Dividing Decimals Divide. Example A 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.

7. 3-3 Dividing Decimals Divide. Example A –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 Divide as with whole numbers.

8. 3-3 Dividing Decimals Example B Jace took a trip in which he drove 350 miles. During the trip his truck used 12.5 gallons of gas. What was his truck’s gas mileage? 350.0 ÷ 12.5 = 3500 ÷ 125 Multiply both numbers by 10. ) 125 3500 Divide as with whole numbers. 2 –250 100 8 0 –1000 0 Jace’s truck’s gas mileage was 28 miles per gallon. To calculate miles per gallon, divide the number of miles driven by the number of gallons of gas used. Helpful Hint

9. 3-3 Dividing Decimals Lesson Quiz Divide. Estimate to check whether each answer is reasonable. 1. 78.2 ÷ 0.04 2. –9.72 ÷ 2.7 3. 18.88 ÷ 1.6 4. 19.5 ÷ 3.25 5. Jordan used 32.46 gallons of gas to drive his van 584.28 miles. How many miles did Jordan get per gallon? –3.6 1,995 11.8 6 18

10. 3-3 Dividing Decimals 6. Divide. 87.3 ÷ 0.09 A. 873 B. 970 C. 977 D. 1230

11. 3-3 Dividing Decimals 7. Divide. –14.72 ÷ (3.2) A. –4.6 B. –5 C. –5.2 D. –5.6

12. 3-3 Dividing Decimals 8. Divide. 19.98 ÷ 1.8 A. 11.4 B. 11.3 C. 11.2 D. 11.1

13. 3-3 Dividing Decimals 9. Divide. 17.15 ÷ 2.45 A. 7 B. 8 C. 9 D. 10

14. 3-3 Dividing Decimals 10. Chris drives at an average speed of 55.45 miles per hour. How long does it take for him to travel a distance of 388.15 miles? A. 6 hours B. 7 hours C. 8 hours D. 9 hours