Factors, Multiples and Primes

Statement Snap

Age 7 to 14
Challenge Level

You'll need to know your number properties to win a game of Statement Snap...

Dozens

Age 7 to 14
Challenge Level

Can you select the missing digit(s) to find the largest multiple?

Factors and Multiples Game

Age 7 to 16
Challenge Level

A game in which players take it in turns to choose a number. Can you block your opponent?

Gabriel's Problem

Age 11 to 14
Challenge Level

Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?

Multiples Sudoku

Age 11 to 14
Challenge Level

Each clue in this Sudoku is the product of the two numbers in adjacent cells.

Number Families

Age 11 to 14
Challenge Level

How many different number families can you find?

How Much Can We Spend?

Age 11 to 14
Challenge Level

A country has decided to have just two different coins, 3z and 5z coins. Which totals can be made? Is there a largest total that cannot be made? How do you know?

Factors and Multiples Puzzle

Age 11 to 14
Challenge Level

Using your knowledge of the properties of numbers, can you fill all the squares on the board?

American Billions

Age 11 to 14
Challenge Level

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...

Diminishing Returns

Age 11 to 14
Challenge Level

How much of the square is coloured blue? How will the pattern continue?

Sieve of Eratosthenes

Age 11 to 14
Challenge Level

Follow this recipe for sieving numbers and see what interesting patterns emerge.

Power Mad!

Age 11 to 14
Challenge Level

Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.

Stars

Age 11 to 14
Challenge Level

Can you work out what step size to take to ensure you visit all the dots on the circle?

Alison's Quilt

Age 11 to 14
Challenge Level

Nine squares are fitted together to form a rectangle. Can you find its dimensions?

Counting Factors

Age 11 to 14
Challenge Level

Is there an efficient way to work out how many factors a large number has?

Route to Infinity

Age 11 to 14
Challenge Level

Can you describe this route to infinity? Where will the arrows take you next?

Differences

Age 11 to 14
Challenge Level

Can you guarantee that, for any three numbers you choose, the product of their differences will always be an even number?

Multiple Surprises

Age 11 to 16
Challenge Level

Sequences of multiples keep cropping up...

Divisibility Tests

Age 11 to 16

This article explains various divisibility rules and why they work. An article to read with pencil and paper handy.

Take Three from Five

Age 11 to 16
Challenge Level

Caroline and James pick sets of five numbers. Charlie chooses three of them that add together to make a multiple of three. Can they stop him?

Product Sudoku

Age 11 to 16
Challenge Level

The clues for this Sudoku are the product of the numbers in adjacent squares.

Funny Factorisation

Age 11 to 16
Challenge Level

Using the digits 1 to 9, the number 4396 can be written as the product of two numbers. Can you find the factors?

Shopping Basket

Age 11 to 16
Challenge Level

The items in the shopping basket add and multiply to give the same amount. What could their prices be?

Beelines

Age 14 to 16
Challenge Level

Is there a relationship between the coordinates of the endpoints of a line and the number of grid squares it crosses?

Latin Numbers

Age 14 to 16
Challenge Level

Can you create a Latin Square from multiples of a six digit number?

Filling the Gaps

Age 14 to 16
Challenge Level

Which numbers can we write as a sum of square numbers?

Expenses

Age 14 to 16
Challenge Level

What is the largest number which, when divided into 1905, 2587, 3951, 7020 and 8725 in turn, leaves the same remainder each time?

LCM Sudoku

Age 14 to 16
Challenge Level

Here is a Sudoku with a difference! Use information about lowest common multiples to help you solve it.