1. Ratios

2. Ratio? Ratio is a way of comparing two or more quantities E.g.
Number of Red Smarties in a box compared to Blue
Number of girls in a class compared to boys

3. 3 ways to Write

4. 2 types of ratios Part to Part – girls in a class to boys in a class
Part to Whole – boys in a class to entire class

5. For example RED & BLUE Smarties Blue : Red 6 : 3 2 : 1 6 BLUE 3 RED
“The Ratio of BLUE to RED Smarties is 2:1”
“The Ratio of BLUE to RED Smarties is 6 to 3”

6. …. Or… 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”

7. 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 greatest common factor

8. Try to simplify these
8:6
18:3
4:8
10:25
7:3
4:3
6:1
1:2
2:5
7:3 !!

9. Ratio Survey Girls to Boys
Students riding the bus to school to students those who do not
Students who play an instrument to class
Students who watch 2 or less hours of TV to those who watch 2 or more

10. Come up with your own survey question!