# Factors and multiples

This collection contains resources from the website 1001mathproblems.com by Sian Zelbo. The topics covered include factors, multiples, primes, and common factors. Each topic is introduced in the form of a puzzle, many of which have several different solutions. The materials are ideal for use with Key Stage 3 students.

## Resources

### Common factor puzzles

This challenge looks at how many common factors greater than 1 are shared by numbers, with bars representing how many factors a pair of numbers have in common. There are three grids to complete with numbers from 1 to 20 to show this relationship. This resource is suitable for Key Stage 3.

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### Hex-a-puzzle 1

This puzzle is about factors and common factors. The numbers from 1 to 9 are to be placed on a grid of 9 hexagons so that the numbers on any straight line are a multiple of 3. This resource is suitable for Key Stage 3.

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### Subtraction snakes

A ‘subtraction snake’ is presented, the rule to find the next number in the snake is to find the difference of the two numbers that come before it. Some questions are posed about starting numbers and end results in work on Highest Common Factors. This resource is suitable for Key Stage 3.

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### Primes around six

A number line is shown with both prime numbers and multiples of six marked on. From the line it is noticeable that the primes are clustered around multiples of six. Students are challenged to explain this and to investigate if this holds for other parts of the number line. This resource is suitable for Key Stage 3...