Mental maths - addition and subtraction

Part ofMathsAdding and subtractingYear 3

What is mental maths?

A boy looks thoughtful with one eyebrow raised, eyes looking up, mouth twisted in thought and one of his fingers pointed next to his cheek.

Mental maths is when you do calculations in your head instead of writing them down.

Sometimes, it's just as quick to do calculations in your head as it is to write down every step.

You can add and subtract using your knowledge of doubles and number bonds.

Even though you're working things out in your head, you can still write down notes to help you if you need.

A boy looks thoughtful with one eyebrow raised, eyes looking up, mouth twisted in thought and one of his fingers pointed next to his cheek.
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Activity: What is mental maths?

Complete this interactive activity to understand how to do mental maths and put your knowledge to the test.

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Using mental maths

There are lots of different tools that help you to do mental addition and subtraction.

Remember, it doesn't have to be done entirely in your head, you can still use a pencil and paper to help.

Find out about some of the tools you can use in the slideshow below.

Image gallerySkip image gallerySlide1 of 3, The number sentence 23 +6 +7 = ? Below this is the same number sentence, but the 7 has been moved into a box next to the number 23. Below this is the number sentence 30 +6 =36., When you add you can rearrange the numbers in the calculation and use your knowledge of number bonds.
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Example 1

32+17+8=?

How can you rearrange the numbers in the calculation and use numbers bonds to find the answer?

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Example 2

14+15=?

What near double could you use to help find the answer?

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Example 3

74-38=?

How can you use a number line to find the difference in this subtraction?

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Play our fun maths game Guardians: Defenders of Mathematica. game

Use your times tables and more maths skills to defeat monsters and reclaim the Kingdom of Mathematica

Play our fun maths game Guardians: Defenders of Mathematica
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More on Adding and subtracting

Find out more by working through a topic