---
title: "Mental addition and subtraction (age 6+)"
description: "Add and subtract a two-digit number and ones mentally and using concrete/pictorial representations"
canonical: https://lightmysky.com/learn/mathematics/mental-addition-and-subtraction-age-6-mt_AKAtWEwpcj
source: https://lightmysky.com/learn/mathematics/mental-addition-and-subtraction-age-6-mt_AKAtWEwpcj.md
retrieved: 2026-10-19
---

> **Agent view.** This is the Markdown twin of the page, for tools and assistants.
> When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md
> API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md
> Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt
> Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json
> Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`.

# Mental addition and subtraction (age 6+)

Add and subtract a two-digit number and ones mentally and using concrete/pictorial representations

Subject: Mathematics · Area: Addition & Subtraction · Ages 6 to 7
Page: https://lightmysky.com/learn/mathematics/mental-addition-and-subtraction-age-6-mt_AKAtWEwpcj

## Ready when they can

- Calculate 36 + 7 = 43 using objects or mentally
- Calculate 52 − 4 = 48 using a number line or mentally
- Explain bridging through 10 when adding ones to a two-digit number

## Lesson: Adding and taking away in your head

You already know how to add and subtract, and you know a two-digit number has a tens digit and a ones digit. Now you can add or take away a small number in your head. Most of the time, the tens digit sits still. You only change the ones.

*(drawing: Hop to 40 first, then hop 3 more to land on 43.)*

**Example.** Mia has 52 stickers and gives away 4. She thinks: 52, take away 2 is 50. Take away 2 more is 48. The tens digit dropped from 5 to 4 because she crossed a ten.

**Tip.** Keep the tens number steady in your head. Change only the ones number. If the ones go past 10, or below 0, one ten hops over. That is called bridging through ten.

**Recap.** Add or subtract the ones first, and let a ten hop over only when the ones bridge past ten.

## Practice

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

## Needs first

- [Adding and subtracting](https://lightmysky.com/learn/mathematics/adding-and-subtracting-mt_mr_Vk7FGzK)
- [The two digits of a two-digit number](https://lightmysky.com/learn/mathematics/the-two-digits-of-a-two-digit-number-mt_THl9GLxwoL)

## Opens up

- [Adding and subtracting two two-digit numbers](https://lightmysky.com/learn/mathematics/adding-and-subtracting-two-two-digit-numbers-mt_UQnAFPs83F)