Year 6 - Maths
Explain how to use long multiplication to multiply a 3-digit by a 2-digit number
Multiplying and dividing by 2-digit numbers
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Study Guides
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 extend their understanding of formal calculation strategies to multiply and divide by 2-digit numbers, explaining when other strategies are more efficient.
Lesson Summary
You will learn to explain how to use long multiplication to multiply a 3-digit by a 2-digit number.
Key Notes
- Calculate the partial products.
- Add the partial products to recombine.
- Regroup when numbers bridge 10, 100 or 1,000
Vocabulary To Learn
- Partial product: Any of the multiplication results we get leading up to an overall multiplication result is a partial product.
- Regroup: The process of unitising and exchanging between place values is known as regrouping.
Common Mistakes To Avoid
- Pupil automatically assume that the largest 3-digit factor will lead to the largest product.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Calculate the partial products. Add the partial products to recombine.
2. Use this key word in a maths sentence and explain it clearly. 'Partial product'
Any of the multiplication results we get leading up to an overall multiplication result is a partial product. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupil automatically assume that the largest 3-digit factor will lead to the largest product. Correction: Encourage pupils to think about the multiplicative structure of 'groups' of and consider e.g. whether 30 groups of 52 or 20 groups of 53 will be greater or smaller.
More Lessons In This Unit
- Dividing by a 2-digit divisor including using long division Study Guide
- Dividing by a 2-digit divisor with a remainder Study Guide
- Dividing numbers with up to 4 digits by multiples of 10 Study Guide
- Explain how to multiply a 3-digit number by a 2-digit number Study Guide
- Explain how to use long multiplication to multiply a 4-digit by a 2-digit number Study Guide
- Explain how to use long multiplication to multiply two 2-digit numbers regrouping ones to tens Study Guide
- Explain how to use long multiplication to multiply two 2-digit numbers with regrouping Study Guide
- Explain how to use the associative law to multiply efficiently Study Guide
- Explain when it is efficient to use factorising or long multiplication to multiply by 2-digits Study Guide
- Solve problems involving remainders in context Study Guide
- Solve problems with 4-digit dividends using factors and long division Study Guide
- Use long division with decimal remainders Study Guide
- Use long division with fraction remainders Study Guide
- Using short and long division to divide by a 2-digit divisor Study Guide
Browse all guides in the Year 6 Maths guide library.