2. Student Progress Chart Lesson Reflection 3-6

3. Math Learning Goal Students will understand decimals.

4. Students will understand decimals by being able to do the following: Learn to write, compare, and order decimals using place value and number lines (3-1) Learn to estimate decimal sums, differences, products, and quotients (3-2) Learn to add and subtract decimals (3-3) Learn to multiply and divide decimals by powers of ten and to convert metric measurements (3-4) Learn to write large numbers in scientific notation (3-5) Learn to multiply decimals by whole numbers and by decimals (3-6)

5. Today’s Learning Goal Assignment Learn to multiply decimals by whole numbers and by decimals. Course 1 3-6 Multiplying Decimals

6. 6 th Grade Math HW Page 122 #10-25 Course 1 3-6 Multiplying Decimals

7. 3-6 Multiplying Decimals Course 1 Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day Problem of the Day

8. Warm Up Multiply. 27,840 754,400 38,060 Course 1 3-6 Multiplying Decimals 120,700 14,112 62,760 1. 87  320 2. 943  800 3. 3,806  10 4. 1,207  100 5. 72  196 6. 120  523

9. Problem of the Day Carmen and Rita sold homemade oatmeal cookies. After 8 days, they had sales totaling $70. Each day, their sales were $0.50 higher than the previous day. What were their sales on the first day? $7.00 Course 1 3-6 Multiplying Decimals

10. Today’s Learning Goal Assignment Learn to multiply decimals by whole numbers and by decimals. Course 1 3-6 Multiplying Decimals

11. Course 1 3-6 Multiplying Decimals Additional 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? 4  0.17 0.17 You can think of multiplication by a whole number as a repeated addition. 0.17 + _____ 0.68

12. Course 1 3-6 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? You can also multiply as you would with whole numbers. Place the decimal point by adding the number of decimal places in the numbers multiplied. 0.17 4  _____ 0.68 2 decimal places + 0 decimal places2 decimal places A 4 lb dumbbell on Earth weighs 0.68 lb on the Moon.

13. Course 1 3-6 Multiplying Decimals Try This: Example 1 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? 7  0.17 0.17 You can think of multiplication by a whole number as a repeated addition. 0.17 + _____ 1.19 0.17

14. Course 1 3-6 Multiplying Decimals Try This: Example 1 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? You can also multiply as you would with whole numbers. Place the decimal point by adding the number of decimal places in the numbers multiplied. 0.17 7  _____ 1.19 2 decimal places + 0 decimal places2 decimal places A 7 lb dumbbell on Earth weighs 1.19 lb on the Moon.

15. Course 1 3-6 Multiplying Decimals Additional Example 2A: Multiplying a Decimal by a Decimal Find the product. A. 0.3  0.4 Multiply. Then place the decimal point. 0.3 0.4  1 decimal place + 1 decimal place2 decimal places 0.12

16. Course 1 3-6 Multiplying Decimals Additional Example 2B: Multiplying a Decimal by a Decimal B. 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 Estimate the product. 0.8 is close to 1. 0.07  1 = 0.07 0.056 is close to the estimate of 0.07. The answer is reasonable.

17. Course 1 3-6 Multiplying Decimals Additional Example 2C: Multiplying a Decimal by a Decimal C. 1.34  2.5 Multiply. Then place the decimal point. 1.34 2.5  2 decimal places + 1 decimal place3 decimal places 670 Estimate the product. Round each factor to the nearest whole number. 1  3 = 3 3.350 is close to the estimate of 3. The answer is reasonable. 2680 3.350

18. Course 1 3-6 Multiplying Decimals Try This: Example 2A Find each product. A. 0.5  0.2 Multiply. Then place the decimal point. 0.5 0.2  1 decimal place + 1 decimal place2 decimal places 0.10

19. Course 1 3-6 Multiplying Decimals Try This: Example 2B B. 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 Estimate the product. 0.9 is close to 1. 0.03  1 = 0.03 0.027 is close to the estimate of 0.03. The answer is reasonable.

20. Course 1 3-6 Multiplying Decimals Try This: Example 2C C. 3.80  3.3 Multiply. Then place the decimal point. 3.80 3.3  2 decimal places + 1 decimal places3 decimal places 1140 Estimate the product. Round each factor to the nearest whole number. 4  3 = 12 12.54 is close to the estimate of 12. The answer is reasonable. 11400 12.540

21. Course 1 3-6 Multiplying Decimals Additional Example 3A: Evaluating Decimal Expressions Evaluate 5x for each value of x. A. x = 3.062 3.062 5  3 decimal places + 0 decimal places3 decimal places 15.310 Substitute 3.062 for x. 5x = 5(3.062) These notations all mean multiply 3 times x. 3 x3x3(x) Remember!

22. Course 1 3-6 Multiplying Decimals Additional Example 3B: Evaluating Decimal Expressions B. x = 4.79 4.79 5  2 decimal places + 0 decimal places2 decimal places 23.95 Substitute 4.79 for x. 5x = 5(4.79)

23. Course 1 3-6 Multiplying Decimals Try This: Example 3A Evaluate 5x for each value of x. A. x = 2.012 2.012 5  3 decimal places + 0 decimal places3 decimal places 10.060 Substitute 2.012 for x. 5x = 5(2.012)

24. Course 1 3-6 Multiplying Decimals Try This: Example 3B B. x = 6.22 6.22 5  2 decimal places + 0 decimal places2 decimal places 31.10 Substitute 6.22 for x. 5x = 5(6.22)

25. Lesson Quiz Find each product. 1. 0.8 2. 0.006  0.07 Evaluate 8x for each value of x. 0.00042 0.056 Insert Lesson Title Here 21.64 6.432 Course 1 3-6 Multiplying Decimals  0.07 $87.40 3. x = 2.7054. x = 0.804 5. “Pick your own” peaches sell for $0.95 per pound. You picked 92 pounds of peaches. How much were you charged?