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
Ratio?

3. 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:
3 to 6
Express the ratio in words:
Express the ratio with a colon:
3:6

5. 2001 Spring Training List the wins to losses by the Cubs : 17 to 14
Team
Wins
Losses
S.D. Padres 16 11
L.A. Dodgers 18 13
Chicago Cubs 17 14
List the wins to losses by the Cubs :
17 to 14
List the losses to wins by the Padres:
11/16
List the Dodgers wins to total games:
18 : 31

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

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

8. 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
Simplifying Ratios

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

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

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

12. 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

13. Practice: Ratios worksheet