1. Common Denominators

2. Why do we need to know this? Comparing fractions >, <, and = Ordering fractions Adding fractions Subtracting fractions

3. Product The answer to a multiplication problem. 6 X 6 = 36

4. What is the product? 7 X 8 = 56

5. What is the product? 8 X 9 = 72

6. Multiple The product of a whole number multiplied times any other whole number. Some multiples of 6 6, 12, 18, 24, 30, 36, 42

7. Name some multiples of 5 5, 10, 15, 20, 25, 30, 35

8. Name some multiples of 7 7, 14, 21, 28, 35, 42, 49

9. Name some multiples of 4 4, 8, 12, 16, 20, 24, 28

10. Name some multiples of 9 9, 18, 27, 36, 45, 54, 63

11. Common Multiple A number that is a multiple of two or more numbers. Some multiples of 3 and 6 3 – 3, 6, 9, 12, 15, 18, 21, 24, 27, 30 6 – 6, 12, 18, 24, 30, 36, 42

12. Common Multiple Some multiples of 3 and 6 3 – 3, 6, 9, 12, 15, 18, 21, 24, 27, 30 6 – 6, 12, 18, 24, 30, 36, 42 Which ones are common?

13. What are some Common Multiples for 2 & 8? 2 – 2, 4, 6, 8, 10, 12, 14, 16, 20… 8 – 8, 16, 24, 32, 40, 48…

14. What are some Common Multiples for 4 & 6? 12, 24, 36, 48, 56, 60

15. What are some Common Multiples for 3 & 7? 21, 42, 63

16. What are some Common Multiples for 5 & 10? 10, 20, 30, 40, 50, 60

17. Least Common Multiple The smallest common multiple of a set of two or more numbers. 6 = 6, 12, 18, 24, 30, 36 5 = 5, 10, 15, 20, 25, 30

18. What is the Least Common Multiple of 3 & 8 8 = 8, 16, 24, 32, 40, 48 3 = 3, 6, 9, 12, 15, 21, 24

19. What is the Least Common Multiple of 4 & 8 8 = 8, 16, 24, 32, 40, 48 4 = 4, 8, 12, 16, 20, 24

20. What is the Least Common Multiple of 6 & 8 8 = 8, 16, 24, 32, 40, 48 6 = 6, 12, 18, 24, 30, 36

21. What is the Least Common Multiple of 4 & 10 10 = 10, 20, 30, 40, 50, 4 = 4, 8, 12, 16, 20, 24

22. What is the Least Common Multiple of 3 & 9 9 = 9, 18, 27, 36, 45, 54 3 = 3, 6, 9, 12, 15, 21,

23. Comparing Fractions Which is bigger?

24. We can use common denominators! What are the common multiples of 4 and 10? 4 – 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48 10 – 10, 30, 30,40, 50, 60, 70, 80 What denominator should we choose?

25. We can use common denominators! 20 X X = = 5 5 2 2 15 16 So which is bigger? 15 or 16? 15 16 20 <

26. But we have to go back to the original fractions! 15 16 20 < 3 8 4 10 <

27. Your Turn Compare using >, < or = 2323 6868 2 6 3 8 <

28. 1 5 4 <