Add 2-digit and 3-digit Numbers

In this lesson, children will learn how to add and subtract numbers with up to 3 digits, using formal written methods of columnar addition and subtraction. They will learn how to add and subtract multiples of 100; add and subtract 3-digit and 1-digit numbers; and add and subtract numbers with up to 3 digits using a formal written method

Target Age:

Lesson Overview

By the end of this unit, students will be able to:

  1. Add and subtract numbers with up to 3 digits, using formal written methods of columnar addition and subtraction;
  2. Add and subtract multiples of 100;
  3. Add and subtract 3-digit and 1-digit numbers;
  4. Add and subtract numbers with up to 3 digits using a formal written method.

Curriculum Alignment: Year 3 Number: Addition and Subtraction

  • Add and subtract numbers mentally, including:
    • a three-digit number and 1s
    • a three-digit number and 10s
    • a three-digit number and 100s
  • Add and subtract numbers with up to 3 digits, using formal written methods of columnar addition and subtraction.
Last updated on: February 25, 2026

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