Year 6 - Maths
Explain how to use long multiplication to multiply a 4-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 4-digit by a 2-digit number.
Key Notes
- Calculate the partial products.
- Add the partial products to recombine.
- Regroup when numbers bridge 10, 100, 1,000, 10,000
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
- Pupils find it challenging to keep track of multiple regroupings in the long multiplication layout and therefore forget to add these to partial products.
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: Pupils find it challenging to keep track of multiple regroupings in the long multiplication layout and therefore forget to add these to partial products. Correction: Estimation can support checking of magnitude. Discuss and agree on a position for regrouped values and continuously model noting and using these.
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 3-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.