Year 5 - Maths
Converting units of length
Calculating with decimal fractions
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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 explain the effect of multiplying and dividing a number by 10, 100 and 1,000 and use their knowledge of multiplying decimal fractions by whole numbers to solve measures problems.
Lesson Summary
You will learn to use knowledge of multiplication and division to convert units of length.
Key Notes
- There are 10 mm in 1 cm.
- There are 100 cm in 1 m.
- There are 1,000 m in 1 km.
- There are 1,000 mm in 1 m.
- There are 10 dm in 1 m.
Vocabulary To Learn
- Convert: To convert means to change a value or expression from one form to another. In this context it means to change from one unit of measurement to another such as from cm to mm.
- Decimetre: A decimetre is a metric unit of length, equal to one-tenth of a metre. Decimetre can be abbreviated to dm.
Common Mistakes To Avoid
- Children may confuse when to multiply or when to divide.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
There are 10 mm in 1 cm. There are 100 cm in 1 m.
2. Use this key word in a maths sentence and explain it clearly. 'Convert'
To convert means to change a value or expression from one form to another. In this context it means to change from one unit of measurement to another such as from cm to mm. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Children may confuse when to multiply or when to divide. Correction: Encourage children to think about which unit of measure is larger e.g. km are larger than m. In a given amount, there will be fewer of the larger unit so we need to divide.
More Lessons In This Unit
- Converting units of mass and capacity Study Guide
- Divide decimal fractions by 1-digit numbers Study Guide
- Divide decimal fractions by 1-digit numbers using written methods Study Guide
- Explain how to multiply and divide a number by 10, 100 and 1,000 Study Guide
- Multiply 1-digit numbers by decimal fractions using written methods Study Guide
- Multiply 1-digit numbers by decimals Study Guide
- Multiply hundredths by whole numbers Study Guide
- Multiply tenths by whole numbers Study Guide
- Multiplying and dividing a number by 10, 100 and 1,000 Study Guide
- Multiplying and dividing a number by 10, 100 and 1,000 including bridging 1 Study Guide
- Predicting the size of a product Study Guide
- Solve measures problems using knowledge of multiplying decimal fractions Study Guide
- The relationship between multiplying by 0.01 and dividing by 100 Study Guide
- The relationship between multiplying by 0.1 and dividing by 10 Study Guide
Browse all guides in the Year 5 Maths guide library.