Dividing Decimals by Decimals

Divisor Quotient Remember! Dividend Dividing Decimals by Decimals

To divide decimals, first write the divisor as a whole number. Multiply the divisor and dividend by the same power of ten. Remember! Dividing Decimals by Decimals

Multiplying the divisor and the dividend by the same number does not change the quotient. 42 ÷ 6 = 7 10  ÷ 60 = 7  10  10 4,200 ÷ 600 = 7 Helpful Hint Dividing Decimals by Decimals

Example: Dividing a Decimal by a Decimal Find the quotient. 5.2 ÷ Multiply the divisor by 10 1, or 10 to make it a whole number. Multiply the dividend by the same power of 10. Think: 1.3 x 10 = x 10 = 52Divide as with whole numbers – ÷ 1.3 = 4 Dividing Decimals by Decimals

Example: Dividing a Decimal by a Decimal 61.3 ÷ Think: 0.36 x 100 = x 100 = 6,130 Multiply the divisor by 10 2, or 100, to make it a whole number. Multiply the dividend by the same power of , Dividing Decimals by Decimals

Example - Continued Place the decimal point in the quotient. Divide as with whole numbers. 36 6, ÷ 0.36 = __ When a repeating pattern occurs, show three dots or draw a bar over the repeating part of the quotient. Dividing Decimals by Decimals

Check It Out Find the quotient ÷ Dividing Decimals by Decimals

Example: Problem Solving Application After driving miles, the Yorks filled up with 10.5 gallons of gas. On average, how many miles did they drive per gallon of gas? 1 Understand the Problem The answer will be the average number of miles per gallon. List the important information: They drove miles. They used 10.5 gallons of gas. Dividing Decimals by Decimals

2 Make a Plan Solve a simpler problem by replacing the decimals in the problem with whole numbers. If they drove 10 miles using 2 gallons of gas, they averaged 5 miles per gallon. You need to divide miles by gallons to solve the problem. Solve 3 First estimate the answer. You can use compatible numbers ÷ ÷ 10 = 20 Dividing Decimals by Decimals

The York family averaged 20.6 miles per gallon Solve Continued Multiply the divisor and dividend by 10. Think: 10.5 x 10 = x 10 = 2,163 Place the decimal point in the quotient. Divide as with whole numbers. Dividing Decimals by Decimals

Look Back4 The answer is reasonable since 20.6 is close to the estimate of 20.

Check It Out: Example 2 After driving miles, the Changs filled up with 8.5 gallons of gas. On average, how many miles did they drive per gallon of gas? 1 Understand the Problem The answer will be the average number of miles per gallon. List the important information: They drove miles. They used 8.5 gallons of gas.

2 Make a Plan Solve a simpler problem by replacing the decimals in the problem with whole numbers. If they drove 10 miles using 2 gallons of gas, they averaged 5 miles per gallon. You need to divide miles by gallons to solve the problem. Solve The Chang family averaged 18.2 miles per gallon.

Look Back4 Use compatible numbers to estimate the quotient ÷ 8.5 → 160 ÷ 8 = 20 The answer is reasonable because 18.2 is close to the estimate of 20. Dividing Decimals by Decimals

1. Identify the quotient. 72  0.9 A. 70 B. 79 C. 80 D. 90 Student Response Systems Dividing Decimals by Decimals

2. Identify the quotient  4.2 A. 8.6 B. 8.8 C. 9.5 D. 9.6 Student Response Systems Dividing Decimals by Decimals

5. Dee bought 5 cups of iced tea for $4.85. What was the cost per cup? A. $0.66 B. $0.69 C. $0.95 D. $0.97 Student Response Systems Dividing Decimals by Decimals