---
title: What is mental math?
description: Learn what mental math is and how doing calculations in your head can help in school and everyday life.
slug: what-is-mental-math
author: Brendan Hodnett, MA
published: '2019-08-05T16:00:48.869Z'
thumbnail: https://cdn-images.understood.org/p0qf7j048i0q/7wJOInRlHEjfUsxgzybicr/3ec600ee10eb370f70fbe9263e86bd6a/G1051328340.jpg
source_url: https://www.understood.org/en/articles/what-is-mental-math
lang: en
---

# What is mental math?

Mental math is a group of skills that allow people to do math “in their head” without using pencil and paper or a calculator. One of these skills is remembering math facts, like 8 × 5 = 40. Other skills include rounding numbers and estimating calculations.

Mental math is useful in everyday life to answer questions like: 

- What is the sale price for this item? 
- Do I have enough cash to buy everything in my cart? 
- Am I getting the correct amount of change from the cashier? 
- When should I leave in order to arrive on time?

Mental math can also help kids understand math concepts better. Using and practicing mental math regularly helps kids improve their [number sense](https://www.understood.org/en/articles/number-sense-what-you-need-to-know).

For example, which is a better deal? Buying a box of 10 packs of gum for $18.00 or buying individual packs for $2.50 each? Use mental math to quickly estimate that the 10-pack must cost less than $2.00 per pack because 10 × 2 = 20. This is a better deal than the second option where each pack costs more than $2.00.

Mental math is useful in other ways too. It keeps math facts from getting rusty. It can also help get to the answer faster.

For example, what is 47 + 65? It’s easier to do this in your head if you break the numbers down into their digits’ values: 40 + 60 = 100 and 7 + 5 = 12. Add those two totals and you get the answer of 112.

Doing mental math requires strong memory skills. Math facts and other number concepts have to be retrieved from long-term memory. Our brains also use a skill called [working memory](https://www.understood.org/en/articles/working-memory-what-it-is-and-how-it-works) to keep track of the steps needed to solve a particular math problem.

When kids struggle with mental math, it doesn’t mean they’re not smart. Kids [develop math skills](https://www.understood.org/en/articles/math-skills-what-to-expect-at-different-ages) at their own pace. Difficulty with mental math could be a matter of needing more time and practice to “catch up.”

Trouble with mental math could also be a sign that your child needs more support to get better at math. Learn about [math challenges in kids and ways to help](https://www.understood.org/en/articles/understanding-your-childs-trouble-with-math).

---

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