Looking for favourite "rich tasks" from the NRICH collection?
These resources have been chosen because they are ideal for developing knowledge and understanding of Factors and Multiples.
Factors and multiples game
A game in which players take it in turns to choose a number. Can you block your opponent?
Dozens
Can you select the missing digit(s) to find the largest multiple?
Divisibility tests
This article explains various divisibility rules and why they work. An article to read with pencil and paper handy.
Factors and multiples - more secondary resources
American billions
Play the divisibility game to create numbers in which the first two digits make a number divisible by 2, the first three digits make a number divisible by 3...
Factors and multiples puzzle
Using your knowledge of the properties of numbers, can you fill all the squares on the board?
Sieve of Eratosthenes
Follow this recipe for sieving numbers and see what interesting patterns emerge.
Take three from five
Caroline and James pick sets of five numbers. Charlie tries to find three that add together to make a multiple of three. Can they stop him?
Stars
Can you work out what step size to take to ensure you visit all the dots on the circle?
Product Sudoku
The clues for this Sudoku are the product of the numbers in adjacent squares.