Year 6 - Maths
Solving problems using column addition and subtraction
Order, compare and calculate with numbers up to 8 digits
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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 use representations to identify and explain patterns in powers of 10 and read numbers with up to 7 digits efficiently. They will order and compare numbers with up to 8 digits and calculate with numbers of this scale.
Lesson Summary
You will learn to solve problems using column addition and subtraction.
Key Notes
- When solving problems, the column addition and column subtraction algorithms are sometimes the most efficient methods.
- If the numbers have different amounts of digits, ensure the digits are aligned in their appropriate place value columns.
- Identify when regrouping is needed when carrying out column addition and subtraction.
Vocabulary To Learn
- Regroup: The process of unitising and exchanging between place values is known as regrouping. For example, 10 tens can be regrouped for one hundred; one hundred can be regrouped for 10 tens.
Common Mistakes To Avoid
- Mis-align numbers when setting up algorithms if the numbers have different amount of digits. When finding 1 missing part out of 3 parts, children may perform two subtractions, which is inefficient.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
When solving problems, the column addition and column subtraction algorithms are sometimes the most efficient methods. If the numbers have different amounts of digits, ensure the digits are aligned in their appropriate place value columns.
2. Use this key word in a maths sentence and explain it clearly. 'Regroup'
The process of unitising and exchanging between place values is known as regrouping. For example, 10 tens can be regrouped for one hundred; one hundred can be regrouped for 10 tens. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Mis-align numbers when setting up algorithms if the numbers have different amount of digits. When finding 1 missing part out of 3 parts, children may perform two subtractions, which is inefficient. Correction: When setting up the algorithm, ensure digits in the same place value place are aligned. When finding 1 missing part of 3 parts, first we add the known parts then we subtract from the whole.
More Lessons In This Unit
- Add and subtract mentally without bridging a boundary Study Guide
- Add multiples of powers of 10 crossing the millions boundary Study Guide
- Compare numbers with up to eight digits Study Guide
- Composition of seven-digit numbers Study Guide
- Determine the value of digits in numbers up to 10 million Study Guide
- Estimate and identify numbers on number lines Study Guide
- Subtract multiples of powers of 10 crossing the millions boundary Study Guide
- Use knowledge of the composition of seven-digit numbers to solve problems Study Guide
- Using patterns in counting sequences Study Guide
Browse all guides in the Year 6 Maths guide library.