This document discusses ratios and how to work with them. It provides examples of ratios using quantities of red and blue smarties. Ratios compare two quantities, such as the number of red smarties to the number of blue smarties. Ratios can be simplified by dividing both numbers by their greatest common factor. The document also explains how to share an amount between two people in a given ratio, such as sharing 16 sweets between Bart and Maggie in a 3:1 ratio.

1. welcome

2. Ratio

3. 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

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

5. …. Or…
RED & BLUE Smarties
6 BLUE 3 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”

6. 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

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

8. Sharing an amount in a given ratio
“Bart and Maggie share a bag of 16 sweets in the ratio 3:1”
This means
“for every 3
sweets Bart
gets, Maggie
gets 1”
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