What this covers
Simplifying Ratios is taught in Year 6 (age 10 to 11, KS2) as a topic to introduce. It sits in the Ratio strand.
Worked example
Simplify the ratio 18 : 24
- Identify highest common factor of 18 and 24, which is 6
- Divide first part: 186 = 3
- Divide second part: 246 = 4
- Write simplified ratio: 3 : 4
Answer: 3:4
Difficulty scale
The sheet generator offers five difficulty settings for this topic.
- Two-part ratios with common factors 2, 5, or 10
- Two-part ratios requiring larger single HCF divisions, up to 12
- Three-part ratios, e.g. 12 : 18 : 24
- Ratios involving decimals or fractions needing scaling to integers first
- Ratios with mixed units requiring unit conversion, e.g. 40 cm to 1.2 m
Common mistakes
- Reversing the order of terms in the ratio
- Simplifying numbers with different units without converting units first
Curriculum links
Indicative matches to National Curriculum for England. Check wording and codes against the official document.
- Solve problems involving the relative sizes of two quantities where missing values can be found by using integer multiplication and division facts.