1. Starter Activity: Mr. Huynh

2. Ratios: Lesson Objectives
WALT: WhatAmLearningToday
Identify simple ratios
Write ratios in their simplest form
Use ratios to find fractions of amounts
Determine equivalent ratios
WILF: WhatImLookingFor
How to identify and write simple ratios
How to use ratios to find fractions of amounts and their equivalences.

3. DO NOW (not later):
Compare the number of boys to girls in the class.

4. The number of boys =
The number of girls =
If we compare boys to girls we get
___ boys to _____ girls.

5. What do we call a comparison between two or more quantities?
We just found the RATIO of boys to girls.
RATIO
Is the ratio of girls to boys the same ?
No, when writing a ratio, ORDER matters.

6. How many basketballs to footballs are there?
For every 4 basketballs there are 6 footballs.
The ratio is 4 to 6 or
The ratio is 2 to 3.

7. Every ratio can be written in 3 ways: Order matters in a ratio.
What are some other ways we can write the ratio of basketball to footballs?
Every ratio can be written in 3 ways:
4 to 6
4 : 6 4 6
First quantity to Second quantity
Careful!!
Order matters in a ratio.
4 to 6
Is NOT the same as
6 to 4
First quantity : Second quantity
First quantity divided by the second quantity (as a fraction).

8. Simplifying Ratios
In the Football & Basketball example, we changed 4:6 to 2:3
This is called Simplifying a ratio
We did it by dividing each number by 2
2 was the highest common factor

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

10. 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” 4 12

11. 16 ÷ 4 = 4 in a share 1 x 4 1 share 4 3 x 4 3 shares 12
“Bart and Maggie share a bag of 16 sweets in the ratio 3:1”
… quicker way….
Another way to think of this 3:1 is shares
Bart gets 3 shares to Maggie’s 1
So there are actually 4 shares
16 sweets shared by 4
16 ÷ 4
= 4 in a share
1 x 4
1 share 4
3 x 4
3 shares 12

12. Write the ratio of sandwiches to coke bottles 3 different ways.
6:8 , 6 to 8, and 6 8
Since a fraction can be simplified, We can simplify the ratio 6/8 to 3/4. The ratio of sandwiches to coke bottles can also be expressed as 3 : 4 or 3 to 4.
In other words, ratios can be simplified to form equivalent ratios.

13. Equivalent Ratios Simplify the following ratios: 4 to 8 10 to 8/
HCF = 4
Step 1 – Write the ratio as a fraction
Step 2 – Simplify the fraction (Find the highest common factor (HCF) of both numbers and divide the numerator and denominator by the HCF).
Step 3 – Write the equivalent ratio in the same form as the question

14. The ratio 2 : 3 can be expressed as
Equivalent Ratios can be formed by multiplying the ratio by any number.
For example, the ratio 2 : 3 can also be written as
4 : 6 (multiply original ratio by 2)
6 : 9 (multiply original ratio by 3)
8 : 12 (multiply original ratio by 4)
The ratio 2 : 3 can be expressed as
2x to 3x (multiply the original ratio by any number x)