1. Multiplying Decimals I can fluently multiply to multiply decimals using the standard algorithm

2. Multiplying Decimals Example 1: Science Application Something that weighs 1 lb on Earth weighs 0.17 lb on the Moon. How much would a 4 lb dumbbell weigh on the Moon? Multiply 4 by 0.17, since 1 pound on Earth is 0.17 pound on the Moon. 17  4 68 Multiply as you would with whole numbers. 4  0.17

3. Multiplying Decimals Additional Example 1 Continued Something that weighs 1 lb on Earth weighs 0.17 lb on the Moon. How much would a 4 lb dumbbell weigh on the Moon? 0.17  4 0.68 Place the decimal point by adding the number of decimal places in the numbers multiplied. A 4 lb dumbbell on Earth weighs 0.68 lb on the Moon. 2 decimal places + 0 decimal places 2 decimal places

4. Multiplying Decimals Example 2 Something that weighs 1 lb on Earth weighs 0.17 lb on the Moon. How much would a 7 lb dumbbell weigh on the Moon? Multiply 7 by 0.17, since 1 pound on Earth is 0.17 pound on the Moon. 17  7 119 Multiply as you would with whole numbers. 7  0.17

5. Multiplying Decimals Example 2 Continued Something that weighs 1 lb on Earth weighs 0.17 lb on the Moon. How much would a 7 lb dumbbell weigh on the Moon? 0.17  7 1.19 Place the decimal point by adding the number of decimal places in the numbers multiplied. A 7 lb dumbbell on Earth weighs 1.19 lb on the Moon. 2 decimal places + 0 decimal places 2 decimal places

6. Multiplying Decimals Example 3: Multiplying a Decimal by a Decimal 0.07  0.8 Multiply. Then place the decimal point. 0.07  0.8 2 decimal places + 1 decimal place3 decimal places; use a placeholder zero 0.056. 0.056 is the product

7. Multiplying Decimals Example 4: Multiplying a Decimal by a Decimal 1.34  2.5 Multiply. Then place the decimal point. 1.34 2.5  2 decimal places + 1 decimal place3 decimal places 670. 3.350 is the product. 2680 3.350

8. Multiplying Decimals Check It Out: Example 5 Find the product. 0.5  0.2 Multiply. Then place the decimal point. 0.5 0.2  1 decimal place + 1 decimal place2 decimal places 0.10

9. Multiplying Decimals Check It Out: Example 6 0.03  0.9 Multiply. Then place the decimal point. 0.03 0.9  2 decimal places + 1 decimal place3 decimal places; use a placeholder zero 0.027 0.027 is the product.

10. Multiplying Decimals Check It Out: Example 7 3.80  3.3 Multiply. Then place the decimal point. 3.80 3.3  2 decimal places + 1 decimal places3 decimal places 1140 12.54 is close to the estimate of 12. The answer is reasonable. 11400 12.540