Ratios

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 ways to Write  

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

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”

…. 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”

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

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

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

Come up with your own survey question!