Year 3 - Maths
Converting between centimetres and millimetres
Measuring length and recording in tables
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupils will continue to measure using appropriate tools and units progressing to using a wider range of measures, including comparing and using mixed units.
Lesson Summary
You will learn to convert between centimetres and millimetres.
Key Notes
- To convert between cm and mm, we can use the relationship between 1 cm and 10 mm.
- To convert between mm, and cm and mm, we can use partitioning.
- Estimating the length or height of an object helps us to decide which unit to use when measuring.
Vocabulary To Learn
- equivalent: When something is equivalent, it is equal in value.
- convert: When we can convert, we change the unit of measurement between millimetres and centimetres but the value remains the same.
Common Mistakes To Avoid
- E.g. 30 mm is not equivalent to 3 cm because 30 is a larger number.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
To convert between cm and mm, we can use the relationship between 1 cm and 10 mm. To convert between mm, and cm and mm, we can use partitioning.
2. Use this key word in a maths sentence and explain it clearly. 'equivalent'
When something is equivalent, it is equal in value. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: E.g. 30 mm is not equivalent to 3 cm because 30 is a larger number. Correction: 10 mm are equivalent to 1 cm. Millimetres are smaller than centimetres and 10 mm are needed to make an equivalent length to 1 cm.
More Lessons In This Unit
- Converting between metres and centimetres Study Guide
- Estimate and measure lengths and heights and record in a table Study Guide
- Estimate in metres and describe a metre in different ways Study Guide
- Measure length and height from zero using whole m or cm Study Guide
- Measuring length and height using cm and mm Study Guide
- Millimetres as a unit of measure and the relationship between them and cm Study Guide
- Solve problems involving length Study Guide
- Solve problems involving length and height Study Guide
- Using graphs to represent lengths and heights Study Guide
Browse all guides in the Year 3 Maths guide library.