Column Addition and Subtraction — Year 3 Lesson Plan
National Curriculum: Mathematics — Number: addition and subtraction, Year 3
Overview
Pupils develop fluency in the formal written methods of column addition and subtraction for 3-digit numbers. They learn to add and subtract with and without regrouping (carrying and exchanging), and apply these methods to solve problems in context.
Learning Objectives
- Add 3-digit numbers using column addition, including carrying.
- Subtract 3-digit numbers using column subtraction, including exchanging.
- Estimate answers using rounding before calculating.
- Apply column methods to solve problems in context.
Key Vocabulary
Suggested Lesson Structure
Quick mental addition and subtraction of multiples of 10 and 100. Introduce the lesson: 'Today we are going to add and subtract numbers that are too big to hold in our heads easily.'
Model column addition step by step: line up digits, add ones first, carry where necessary. Repeat for column subtraction with exchanging. Use place-value counters alongside the written method to make the regrouping concrete.
Pupils work through a set of calculations, first with manipulatives, then in written form. Include at least two calculations requiring carrying/exchanging. Check answers by swapping with a partner.
Pupils complete a mixed set of additions and subtractions, then apply the method to a two-step word problem.
Display a calculation with a deliberate error. Ask pupils to find the mistake and explain what went wrong. Reinforce correct layout and regrouping.
Common Misconceptions
- Pupils write a carried digit in the wrong column or forget to add it.
- When exchanging in subtraction, pupils subtract the smaller digit from the larger regardless of position.
- Misaligning digits — always stress lining up by place value, not by the decimal point or the left side.
Prior Knowledge
Pupils should already be able to:
- Secure knowledge of place value for 3-digit numbers.
- Ability to add and subtract 2-digit numbers mentally.
- Understanding of the relationship between addition and subtraction.
Want a personalised version of this lesson?
Use Staffroom to generate a complete lesson plan tailored to your class — add context about ability, recent learning, or specific pupils and get a plan ready to teach. Free trial, no card required.