---
title: "Grouping numbers to add"
description: "Understand and apply the associative property of addition: when adding three numbers, any two can be added first"
canonical: https://lightmysky.com/learn/mathematics/grouping-numbers-to-add-mt_T76hKqXf0z
source: https://lightmysky.com/learn/mathematics/grouping-numbers-to-add-mt_T76hKqXf0z.md
retrieved: 2026-10-19
---

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# Grouping numbers to add

Understand and apply the associative property of addition: when adding three numbers, any two can be added first

Subject: Mathematics · Area: Addition & Subtraction · Ages 6 to 7
Page: https://lightmysky.com/learn/mathematics/grouping-numbers-to-add-mt_T76hKqXf0z

## Ready when they can

- Solve 2 + 6 + 4 by first adding 6 + 4 = 10, then 2 + 10 = 12
- Explain that grouping addends differently gives the same total
- Choose which two numbers to add first to make the calculation easier

## Lesson: Grouping numbers to add

You already know you can add two numbers in any order. Grouping works in a similar way. When you add three numbers, you can add any two of them first, then add the third one. The total stays the same either way.

*(drawing: You can add 6 and 4 first to make 10, then add 2 to get 12.)*

**Example.** Ben adds 3 + 7 + 6. He notices that 3 and 7 make 10, an easy number. So he groups those first: 3 + 7 = 10. Then he adds 10 + 6 = 16. Grouping the numbers a different way did not change the answer.

**Tip.** Look for two numbers that make a friendly number like 10. Add those first, then add the last number. The total never changes, no matter which pair you pick first.

**Recap.** You can add any two numbers first when adding three of them, and the total always stays the same.

## Practice

17 questions on this page, each with its working shown.

## Needs first

- [Addition in any order](https://lightmysky.com/learn/mathematics/addition-in-any-order-mt_QCgbiVrwnp)

## Opens up

- [Adding Three Small Numbers](https://lightmysky.com/learn/mathematics/adding-three-small-numbers-mt_Zx1xZM-RbX)