---
title: "Fluent addition and subtraction"
description: "Recall and use addition and subtraction facts to 20 fluently, and derive and use related facts up to 100"
canonical: https://lightmysky.com/learn/mathematics/fluent-addition-and-subtraction-mt_3e_PQxwC12
source: https://lightmysky.com/learn/mathematics/fluent-addition-and-subtraction-mt_3e_PQxwC12.md
retrieved: 2026-10-19
---

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# Fluent addition and subtraction

Recall and use addition and subtraction facts to 20 fluently, and derive and use related facts up to 100

Subject: Mathematics · Area: Addition & Subtraction · Ages 6 to 7
Page: https://lightmysky.com/learn/mathematics/fluent-addition-and-subtraction-mt_3e_PQxwC12

## Ready when they can

- Rapidly recall 7 + 8 = 15 and 15 − 8 = 7
- Use 6 + 4 = 10 to derive 60 + 40 = 100
- Derive 35 + 5 = 40 from knowledge that 5 + 5 = 10

## Lesson: Fast facts, big jumps

You already know addition and subtraction facts up to 20. Now it is time to make them fast, like snapping your fingers. No stopping to count on fingers, just remember them.

*(drawing: 7 + 8 = 15. Hop 8 spaces from 7 and land on 15.)*

**Example.** Mia knows 6 + 4 = 10. She uses that fact to solve 60 + 40. She thinks: 6 tens plus 4 tens make 10 tens, which is 100.

**Tip.** A subtraction fact hides inside every addition fact. If you know 9 + 7 = 16, you already know 16 minus 7 = 9. Same fact, just flipped around.

**Recap.** Learn your facts to 20 by heart, then use the same facts to jump to bigger numbers in tens.

## Practice

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

## Needs first

- [Addition and subtraction within 20](https://lightmysky.com/learn/mathematics/addition-and-subtraction-within-20-mt_m1W6nTQJ2b)
- [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

- [Fluent addition and subtraction (age 9+)](https://lightmysky.com/learn/mathematics/fluent-addition-and-subtraction-age-9-mt_Yw1_4Nfsql)