New
New
Year 6

# Use multiplication and division to calculate unknown values in ratio problems

You can use multiplication and division to calculate unknown values in ratio problems.

New
New
Year 6

# Use multiplication and division to calculate unknown values in ratio problems

You can use multiplication and division to calculate unknown values in ratio problems.

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## Lesson details

### Key learning points

1. Different representations can be used to show the same mathematical structure.
2. Ratio tables show the multiplicative relationship between variables.

### Common misconception

Seeing multiplication and division as inverse operations e.g. dividing by 2 and multiplying by half.

Encourage pupils to express the relationships between values using both multiplication and division.

### Keywords

• Ratio - A ratio shows the relative sizes of 2 or more values and allows you to compare a part with another part in a whole

• For every - For every allows you to talk about the relative sizes of the values e.g. for every 2 squares there is 1 triangle

Make links to known times table facts and encourage pupils to think about the relationships between values as both multiplication and division. Ask them to explain which relationship they find easier to think about and why.
Teacher tip

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Starter quiz

### 6 Questions

Q1.
What is 8 times as many as 5?
Q2.
How many 8s are there in 24?
Q3.
How many times greater than 3 is 27?
24
3
6
10
Q4.
Which phrases describe the quiz team in this image
For every 2 chidlren there are 3 adults
For every 3 adults there are 3 children
For every 3 children there are 4 adults
Q5.
Each quiz team is made up of 3 adults and 4 children. If there are 35 people taking part, which equation represents how many of them are adults?
$$3 + 35 = 38$$
$$4 \times 5 = 20$$
Correct answer: $$3 \times 5 = 15$$
$$3 \times 7 = 21$$
Q6.
Each quiz team is made up of 3 adults and 4 children. If there are 5 teams taking part, how many children will there be in total?
7
15
32
31

## Exit quiz

### 6 Questions

Q1.
A quiz team is made up of 2 adults and 3 children. How many quiz teams does this image represent?
2
3
5
Q2.
How many children are represented in this image?
3
4
9
Q3.
How many adults are represented in this image?
2
4
6
Q4.
How many people in total are represented in this image?
5
16
25
Q5.
What does the 5 in this equation represent in the image? $$5 \times 4 = 20$$
The number of children
What does the 4 in this equation represent in the image? $$5 \times 4 = 20$$