1. Let’s see what you know! Mrs. Flynn’s Topic 3 Math Review Are you ready? Here are the concepts we’re covering in math.

2. Multiplying by Multiples of Ten 4 X 20 = ? Look for the basic fact to help you. 4 X 2 tens = 8 tens So… 4 X 20 = 80 Basic fact

3. Practice Multiplying Tens 1.3 X 2 tens = 2.6 X 5 tens = 3.8 X 6 tens = 4.7 X 20 = 5.7 X 80 = 6.6 X 90 = 7.4 X 50 = 6 tens 30 tens 48 tens 140 560 540 200 (60) (300) (480)

4. Nicole builds 3 birdhouses in an hour & works 40 hours weekly. How many birdhouses does she make each week? 3 birdhouses X 40 hours =

5. There are 20 chickens on John’s farm. Each lays 2 eggs each day. How many eggs can John collect each week? 2 eggs X 20 chickens X 7 days =

6. Multiplying Using Patterns Look for the basic fact to help you. 3 X 3 hundreds = 9 hundreds So… 3 X 300 = 900 Basic fact

7. Multiplication Patterns Use the same idea to help you multiply larger numbers. 6 X 4 = 24 6 X 40 = 240 6 X 400 = 2,400 6 X 4,000 = 24,000

8. Practice! Find each product. 1. 5 X 90 = 2.70 X 700 = 3.6 X 5,000 = 4.600 X 70 = 5.8,000 X 3 = 450 49,000 30,000 42,000 24,000

9. Estimate means… to find a number close to the exact number.

10. Rounding to Estimate Products Cheyenne collects books. She has 8 boxes. Each box holds about 38 books. How many books does she have? (38 rounds to 40)

11. Rounding to Estimate Products Christian collects books. He has 18 shelves. Each shelf holds about 115 books. About how many books does he have? (115 rounds to 100) (18 rounds to 20)

12. Rounding to Estimate Products Corey collects football cards. He has 5 albums. Each album holds 45 cards. About how many football cards does Corey have? (45 rounds to 50)

13. Now it’s your turn! 1.567 X 5 2.674 X 22 3.7,881 X 6 4.3,580 X 3 5.6 X 251 6.4 X 3,679 7.72 X 1,814 600 X 5 = 3,000 700 X 20 = 14,000 8,000 X 6 = 48,000 4,000 X 3 = 12,000 6 X 300 = 1,800 4 X 4,000 = 16,000 70 X 2,000 = 140,000

14. Distributive Property with Arrays What is an array? An array is an arrangement of objects into rows and columns. 5 rows of 10 5 rows of 1

15. Practice! Draw arrays to help. 1.73 X 7 2.35 X 6 3.59 X 4 4.46 X 9 5.26 X 3 70 X 7 = 490 30 X 6 = 180 50 X 4 = 200 40 X 9 = 360 20 X 3 = 60 3 X 7 = 21 5 X 6 = 30 9 X 4 = 36 6 X 9 = 54 6 X 3 = 18 490 + 21 = 511 180 + 30 = 210 200 + 36 = 236 360 + 54 = 414 60 + 18 = 78

16. Multiplication with Regrouping Step One: Multiply the ones & regroup. +3

17. Multiplication with Regrouping Step Two: Multiply the tens & add the extra tens. +3

18. Multiplication with Regrouping Try some with me! +2 + 2 = 23

19. Multiplication with Regrouping Try some with me! +1 + 1 = 36

20. Multiplication with Regrouping Try some with three digits! +5 + 5 = 17 +1 + 1 = 49

21. Multiplication with Regrouping Try some with three digits! +2 + 2 = 18 +1 + 1 = 25

22. Multiplication with Regrouping Try some multiplication with money! +2 + 2 = 37 +3 + 3 = 10

23. Multiplication with Regrouping Try some multiplication with money! +7 + 7 = 79 +7 + 7 = 39 + 3 = 11 +3

24. What is the Associative Property? When the grouping of factors is changed, the product remains the same.

25. What is the Commutative Property? When the order of factors is changed, the product remains the same.

26. Multiplying 3 Factors The parentheses tell which factors to multiply first. I know you’re going to do this on a piece of paper, right?

27. Multiplying 3 Factors The parentheses tell which factors to multiply first. And you can do this in your head, right?

28. Multiplying 3 Factors The parentheses tell which factors to multiply first. It’s all switched up, but it’s the same idea…

29. Multiplying 3 Factors If there are no parentheses, multiply the smaller numbers first. NO PROBLEMO, MAN! Okay. No parentheses?

30. Pencil, paper, and practice! 1.6 X 6 X 3 = 2.3 X 9 X 1 = 3.8 X 5 X 6 = 4.4 X 3 X 11 = 5.7 X 0 X 21 = 18 X 6 = 3 X 9 = 30 X 8 = 11 X 12 = 0 X 21 = 108 27 240 132 0

31. Problem Solving Fun! To raise money for the food drive, Kaitlyn sold 5 boxes of cards. Connor sold 3 boxes of candy bars. If a box of cards costs $2.99 and a box of candy bars costs $5.25, how much did they earn? +4 +1

32. 2 Digit by 2 Digit Multiplication

33. 36 X 23

34. Multiply the ones. 36 X 23 3 X 6 = 18 Regroup the ten. 3 X 3 = 9 and one more is 10.

35. 36 X 23 108 1

36. 36 X 23 108 Cross out the 1 after you use it. 1

37. NOW THINK: “I am multiplying 36 X 20.” 36 X 23 108

38. 1 st THINK: “I am multiplying by tens so I need a zero.” 36 X 23 108 0

39. 36 X 23 108 20 1 1 2 X 6 = 12 Put down the 2 and regroup the 1.

40. 36 X 23 108 720 1 1 2 X 3 = 6 and 6 + 1 = 7

41. 36 X 23 108 720 1 1 Cross out the number you regrouped after you add it.

42. Since multiplication is a form of addition, we need to group our answers together. Add the two partial products to get the final product.

43. 36 X 23 108 + 720 828 8 + 0 = 8 0 + 2 = 2 1 + 7 = 8

44. Exponents The number that is repeatedly multiplied is called the ___________. The _________________ shows the number of times the base is used as a factor. The base is multiplied 3X

45. Write in Exponential Notation 1.Four squared = 2.Two cubed = 3.5 X 5 X 5 X 5 = 4.4 X 4 X 4 X 4 X 4 = 5.6 to the 5 th power =

46. Write in Standard Form 1.Four squared == 2.Two cubed == 3.5 X 5 X 5 X 5 == 4.4 X 4 X 4 X 4 X 4 = = 5.6 to the 3 rd power = = 4 x 4 = 16 1,024 625 8 216