Mental maths and algebra (magic)

Recently, I was shown a “magic” trick on social media showing how to quickly multiply the numbers 96 and 97 together. Essentially you expand (100-4)(100-3), instead of calculating 96 x 97. It reminded me of the Core Maths resource Mental maths and algebra.

The resource introduces two similar “magic” tricks and asks students to explain how they work. The first looks at how to square two-digit numbers ending in 5:

 

The second is for squaring any two-digit number:

 

 The resources can be found in our Core Maths collection: https://www.stem.org.uk/core-maths/resources​ 

You might also be interested Nix the Tricks- a recent addition to the STEM Learning online resource collection that provides alternative methods to all those maths tricks students sometime use.

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Subject(s)Mathematics
Age16-19, FE/HE
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