Year 5 - Maths
Predicting the size of a product
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 explain how to use the size of one number in a multiplication to predict the size of the product.
Key Notes
- If one factor is made ___ times the size and the other factor remains the same, the product will be ___ times the size.
- When a number is multiplied by a value less than one, the product is smaller than the original number.
- When a number is multiplied by a value greater than one, the product is greater than the original number.
Vocabulary To Learn
- Product: The product is the result of two or more numbers multiplied together.
- Factor: Factors are integers that are multiplied together to get a product.
Common Mistakes To Avoid
- Children may think that multiplication always makes things larger. Children may scale incorrectly.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
If one factor is made ___ times the size and the other factor remains the same, the product will be ___ times the size. When a number is multiplied by a value less than one, the product is smaller than the original number.
2. Use this key word in a maths sentence and explain it clearly. 'Product'
The product is the result of two or more numbers multiplied together. 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 think that multiplication always makes things larger. Children may scale incorrectly. Correction: When a number is multiplied by a value less than 1, the product is smaller than the original number - multiplication doesn't always make things larger. Compare numbers: if one factor is made ___ times the size, the product will be ___ times the size.
More Lessons In This Unit
- Converting units of length Study Guide
- 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
- 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.