Year 5 - Maths
Multiply a 2-digit number by a 1-digit number using partitioning and representations (one regroup)
Multiplication by partitioning leading to short multiplication (2 by 1-digit)
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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 multiply a 2-digit number by a single-digit number using partitioning and representations using expanded multiplication and using short multiplication.
Lesson Summary
You will learn to use an array to represent multiplication and use place value in an array to represent multiplication of a 2-digit number.
Key Notes
- Partitioning allows us to multiply the tens and then the ones and recombine the products.
- The grid can represent the array.
- Multiply the ones and tens separately and recombine.
Vocabulary To Learn
- array: An array is the layout of items (such as objects, numbers, etc.) arranged in rows and/or columns.
- product: The result of two or more values multiplied together.
- regroup: The process of unitising and exchanging between place values is known as regrouping.
Common Mistakes To Avoid
- Pupils may not regroup correctly if they do not understand the place value of digits in a factor.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Partitioning allows us to multiply the tens and then the ones and recombine the products. The grid can represent the array.
2. Use this key word in a maths sentence and explain it clearly. 'array'
An array is the layout of items (such as objects, numbers, etc.) arranged in rows and/or columns. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils may not regroup correctly if they do not understand the place value of digits in a factor. Correction: Encourage pupils to use the stem sentences / array to identify when they may need to regroup.
More Lessons In This Unit
- Estimate and multiply a 2-digit by a 1-digit number using expanded and short multiplication Study Guide
- Multiply a 2-digit number by a 1-digit number using expanded multiplication (no regroups) Study Guide
- Multiply a 2-digit number by a 1-digit number using expanded multiplication (regrouping 10s to 100s) Study Guide
- Multiply a 2-digit number by a 1-digit number using expanded multiplication (regrouping 1s to 10s) Study Guide
- Multiply a 2-digit number by a 1-digit number using partitioning Study Guide
- Multiply a 2-digit number by a 1-digit number using partitioning and representations (two regroups) Study Guide
- Multiply a 2-digit number by a 1-digit number using short multiplication (no regroups) Study Guide
- Multiply a 2-digit number by a 1-digit number using short multiplication (regrouping 10s to 100s) Study Guide
- Multiply a 2-digit number by a 1-digit number using short multiplication (regrouping 1s to 10s) Study Guide
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