# TES Maths ROTW: Prime factor puzzle

Help students get to grips with prime factor decomposition using this thought-provoking puzzle, recommended by TES Maths

## TES Maths Resource of the Week

### What is it?

In this puzzling activity, students are presented with a grid of numbers. Each number is surrounded by four empty boxes. Pupils are tasked with the job of filling the empty boxes with the central number's prime factors.

But there is, of course, a twist! The completed grid must work for all of the numbers that are in it. So, it's not enough for students to simply list the prime factors of each number; they must also consider the shared prime factors of the numbers around it. As a result, this puzzle gets quite tricky, quite quickly.

### How can it be used?

For me, this is the ideal example of something I feel incredibly passionate about: purposeful practice. Learners have the opportunity to practice the key skill (in this case, prime factor decomposition) in an interesting and engaging way. There is also the opportunity to discuss the properties of these numbers by asking questions such as, 'How can I tell if a number has 2 as one of its prime factors?'

More importantly, students also get the chance to develop crucial skills such as problem solving, logical reasoning and deduction, all of which will serve them in good stead for any future mathematical challenges.

Craig Barton

Craig is a secondary maths teacher in the North of England.

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