Maths Made Fun / Number Ninja / Lesson 2

Mental Maths Superpowers

Being fast at mental maths is like having a superpower. Here are some tricks that make you look like a genius!

Adding 9: Instead of adding 9, add 10 and subtract 1. So 47 + 9 = 47 + 10 - 1 = 56.

Doubling and halving: To multiply by 4, just double it twice! 13 x 4 = 13 x 2 x 2 = 26 x 2 = 52.

Rounding trick: For 198 + 347, round 198 to 200, add to get 547, then subtract 2 to get 545.

67 + 9:67 + 10 - 1 = 76

25 x 4:25 x 2 = 50, 50 x 2 = 100

299 + 456:300 + 456 = 756, then 756 - 1 = 755

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What's the quickest way to work out 56 + 9 in your head?