# Changing ratios

I can find quantities given a change in the ratio.

# Changing ratios

I can find quantities given a change in the ratio.

## Lesson details

### Key learning points

- It is important to preserve the relationship between the parts of a ratio.
- Changing this relationship would change the ratio.
- When the ratio changes, the quantities can be worked out by using equivalent ratios.

### Common misconception

Treating the ratio as the total amount. For example sweets : chocolates in the ratio 6 : 7 and 2 chocolates are eaten, thinking the ratio must now be 6 : 5

Looking at how these problems are formed in learning cycle 1 will help and getting pupils to explore how the ratio changes when things are added or removed.

### Keywords

Proportion - A part to whole (sometimes part to part) comparison. If two things are proportional then the ratio of part to whole is maintained and the multiplicative relationship between parts is also maintained.

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.

LCM - LCM is an abbreviation for lowest common multiple.

Lowest common multiple - The lowest common multiple is the lowest number that is a multiple of two or more numbers.

### 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).

## Video

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