1. 5 Minute Check Complete on your homework. Estimate and multiply. 1. 9.7 x 3 2. 3.4 x 5 3. 17.5 x 8 4. 3.48 x 25

2. 5 Minute Check Complete on your homework. Estimate and multiply. 1. 9.7 x 3

3. 5 Minute Check Complete on your homework. Estimate and multiply. 1. 9.7 x 3 ≈ 30 9.7 x 3 29.1

4. 5 Minute Check Complete on your homework. Estimate and multiply. 2. 3.4 x 5

5. 5 Minute Check Complete on your homework. Estimate and multiply. 2. 3.4 x 5 ≈ 15 3.4 x 5 17.0

6. 5 Minute Check Complete on your homework. Estimate and multiply. 3. 17.5 x 8

7. 5 Minute Check Complete on your homework. Estimate and multiply. 3. 17.5 x 8 ≈ 144 17.5 x 8 140.0

8. 5 Minute Check Complete on your homework. Estimate and multiply. 4. 3.48 x 25

9. 5 Minute Check Complete on your homework. Estimate and multiply. 4. 3.48 x 25 ≈ 75 3.48 x 25 1740 6960 87.00

11. Flashcards

12. Friday, Oct 2 Lesson 3.2/3.4 Estimating and Multiplying Decimals by Decimals

13. Multiplying Decimals by Decimals Objective: To understand how to estimate and multiply decimals by decimals.

14. Multiplying Decimals by Decimals To multiply decimals, multiply as normal and then place the decimal point.

15. Multiplying Decimals by Decimals Find. 8.7 x 2.8 Estimate?

16. Multiplying Decimals by Decimals Find. 8.7 x 2.8 ≈ 27 Estimate? 9 x 3 = 27 Step 1 - ? 9 3

17. Multiplying Decimals by Decimals Find. 8.7 x 2.8 ≈ 27 8.7 x 2.8 Step 2 - ? 9 3

18. Multiplying Decimals by Decimals Find. 8.7 x 2.8 ≈ 27 8.7 x 2.8 696 1740 2436 Step 3 - ? 9 3

19. Multiplying Decimals by Decimals Find. 8.7 x 2.8 ≈ 27 8.7 1 decimal place x 2.8 1 decimal place 696 2 total decimal places 1740 24.36 Does this seem reasonable? 9 3

20. Multiplying Decimals by Decimals Find. 8.7 x 2.8 ≈ 27 8.7 1 decimal place x 2.8 1 decimal place 696 2 total decimal places 1740 24.36 Does this seem reasonable? Yes, since 24.36 ≈ 27 9 3

21. Multiplying Decimals by Decimals Are today’s estimates going to be more or less accurate than yesterday’s estimates?

22. Multiplying Decimals by Decimals Find..98 x 7.3 Do this on your own.

23. Multiplying Decimals by Decimals Find..98 x 7.3 Estimate?

24. Multiplying Decimals by Decimals Find..98 x 7.3 ≈ 7 Actual? 1 7

25. Multiplying Decimals by Decimals Find..98 x 7.3 ≈ 7.98 2 decimal place x 7.3 1 decimal place 294 3 total decimal places 6860 7.154 Does this seem reasonable? 1 7

26. Multiplying Decimals by Decimals Find..98 x 7.3 ≈ 7.98 2 decimal place x 7.3 1 decimal place 294 3 total decimal places 6860 7.154 Does this seem reasonable? Yes, since 7.154 ≈ 7 1 7

27. Multiplying Decimals by Decimals Find. 3.6 x 0.05 Do this on your own.

28. Multiplying Decimals by Decimals Find. 3.6 x 0.05 Estimate?

29. Multiplying Decimals by Decimals Find. 3.6 x 0.05 ≈ 0 Actual? 4 0

30. Multiplying Decimals by Decimals Find. 3.6 x 0.05 ≈ 0 3.6 x.05 180 0000 0.180 4 0

31. Multiplying Decimals by Decimals Find. 0.112 x 7.2 Do this on your own.

32. Multiplying Decimals by Decimals Find. 0.112 x 7.2 Estimate?

33. Multiplying Decimals by Decimals Find. 0.112 x 7.2 ≈ 0 Actual? 0 7

34. Multiplying Decimals by Decimals Find. 0.112 x 7.2 ≈ 0.112 x 7.2 224 7840 0.8064 0 7

35. Multiplying Decimals by Decimals If your lawn mower gets 50 miles per gallon and the tank holds 2 gallons, how far could you travel on a tank of gas? Do this on your own.

36. Multiplying Decimals by Decimals If your lawn mower gets 50 miles per gallon and the tank holds 2 gallons, how far could you travel on a tank of gas? 1 gallon 1 gallon 50 miles 50 miles 50 x 2 = 100 miles

37. Multiplying Decimals by Decimals Mr. Avery’s car can travel 28.45 miles on one gallon of gas. If his gas tank holds 11.5 gallons, how far can he travel on one tank? Do this on your own.

38. Multiplying Decimals by Decimals Mr. Avery’s car can travel 28.45 miles on one gallon of gas. If his gas tank holds 11.5 gallons, how far can he travel on one tank? Estimate; 28 x 12 = 336 28.45 x 11.5 14225 28450 +284500 327.175

39. Multiplying Decimals by Decimals A giraffe can run up to 46.9 feet per second. How far could it run in 1.8 seconds? Justify your answer. Do this on your own.

40. Multiplying Decimals by Decimals A giraffe can run up to 46.9 feet per second. How far could it run in 1.8 seconds? Justify your answer. 46.9 x 1.8 ≈ 94 46.9 x 1.8 3752 4690 83.42 47 2

41. Multiplying Decimals by Decimals You want to purchase a pair of shoes that cost $89. Sales tax is 5.5%. What will you pay for the shoes? Do this on your own.

42. Multiplying Decimals by Decimals You want to purchase a pair of shoes that cost $89. Sales tax is 5.5%. What will you pay for the shoes?.055(tax ) 89.00 x 89 + 4.90 (rounded tax) 495 93.90 4400 4.895 (tax) Since this is money 4.895 is $4.90, 89 + 4.90 is $93.90 OR

43. Multiplying Decimals by Decimals You want to purchase a pair of shoes that cost $89. Sales tax is 5.5%. What will you pay for the shoes? 100% + 5.5% = 1 + 0.055 = 1.055 1.055 x 89 9 495 84400 93.895

44. Multiplying Decimals by Decimals Pears cost $0.92 per pound and apples cost $1.10 per pound. If you bought 3.7 pounds of pears and 2.1 pounds of apples, how much would it cost? Do this on your own.

45. Multiplying Decimals by Decimals Pears cost $0.92 per pound and apples cost $1.10 per pound. If you bought 3.7 pounds of pears and 2.1 pounds of apples, how much would it cost? Estimate $1 x 4 = $4 and $1 x 2 = $2, $4+$2=$6 3.7 1.10 3.40 x.92 x 2.1 +2.31 74 110 5.71 +3330 2200 3.404 2.310

46. Multiplying Decimals by Decimals Determine whether the following statement is always, sometimes or never true. The product of two decimals less than 1 is less than either of the factors. Give examples to support your answer.

47. Multiplying Decimals by Decimals Determine whether the following statement is always, sometimes or never true. The product of two decimals less than 1 is less than either of the factors. Always. For example, 0.3 x 0.5 =.15, which is less than 0.3 and 0.5 0.75 x 0.6 = 0.45

48. Multiplying Decimals by Decimals Evaluate the expression, 0.3( 3 - 0.5) Do this on your own.

49. Multiplying Decimals by Decimals Evaluate the expression, 0.3( 3 - 0.5) 0.3(2.5) 0.75 2.5 x.3.75

50. Multiplying Decimals by Decimals Please complete the Mid-Chapter Check on page 214 and bring to my desk when complete. Agenda Notes No Homework Mid-Chapter 3 Quiz Monday, Oct 5