1. Ratios

2. Ratio? Ratio is a way of comparing two or more quantities Examples: ◦Number of oranges to apples ◦Number of girls in a class compared to boys

3. There are 3 ways to express ratios : There are 3 ways to express ratios : As a fraction - ¾ Using a colon - 3:4 Using the word “to” - 3 to 4

4. What is the ratio of cats to mice? Number of Cats: 3 Number of Mice: 6 Express the ratio as a fraction: Express the ratio in words: Express the ratio with a colon: 3 to 6 3:6

5. TeamWinsLosses S.D. Padres1611 L.A. Dodgers1813 Chicago Cubs1714 2001 Spring Training List the wins to losses by the Cubs :17 to 14 Wins to games played by the Cubs: 17 to 31 List the losses to wins by the Padres:11/16 Losses to games played by the Padres :11/27

6. TeamWinsLosses S.D. Padres1611 L.A. Dodgers1813 Chicago Cubs1714 2001 Spring Training List the Dodgers wins to total games: 18 : 31 List the Dodgers losses to wins: 13 : 18

7. RED & BLUE Smarties 6 BLUE3 RED “The Ratio of BLUE to RED Smarties is 6 to 3 Blue : Red 6 : 3 Which symplifies to 2 : 1 “The Ratio of BLUE to RED Smarties is 6 Ratio Example Problems

8. …. Or… We can compare Red to Blue Smarties! RED & BLUE Smarties 6 BLUE3 RED “The Ratio of RED to BLUE Smarties is 3 to 6” Red : Blue 3 : 6 1 : 2 “The Ratio of RED to BLUE Smarties is 1:2” “For every RED Smartie, there are 2 BLUES”

9. Simplifying Ratios In the Smarties example, we changed 6:3 to 2:1 This is called Simplifying a ratio We did it by dividing each number by 3 3 was the largest common factor

10. Try to simplify these 8:2 18:3 4:8 5:25 5:2 4:1 6:1 1:2 1:5 5:2 !!

11. Practice With Equivalent Ratios Find an equivalent ratio by simplifying:  Divide by 30 # 1 # 2  Divide by 3 # 3  Divide by 25 Equivalent ratios make the same comparison.

12. Practice With Equivalent Ratios Fill in the blank to make an equivalent ratio:  Multiply by 5 # 4 # 5 # 6  Multiply by 10  Divide by 2 ? ? ?

13. Sharing an amount in a given ratio “Bart and Maggie share a bag of 16 life savers with the ratio of 3:1” This means “for every 3 life savers Bart gets, Maggie gets 1” 4 Lifesavers for Maggie 12 Lifesavers for Bart

14. Practice: Ratios worksheet