List

Factors, multiples and primes

Statement Snap
problem
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Statement Snap

Age
7 to 14
Challenge level
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You'll need to know your number properties to win a game of Statement Snap...
Xavi's T-shirt
problem

Xavi's T-shirt

Age
7 to 16
Challenge level
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How much can you read into a T-shirt?
Dozens
problem
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Dozens

Age
7 to 14
Challenge level
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Can you select the missing digit(s) to find the largest multiple?
American Billions
problem
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American Billions

Age
11 to 14
Challenge level
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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
problem
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Factors and Multiples Puzzle

Age
11 to 14
Challenge level
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Using your knowledge of the properties of numbers, can you fill all the squares on the board?
Multiples Sudoku
problem
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Multiples Sudoku

Age
11 to 14
Challenge level
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Each clue in this Sudoku is the product of the two numbers in adjacent cells.
How much can we spend?
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How much can we spend?

Age
11 to 14
Challenge level
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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?
Diminishing Returns
problem
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Diminishing Returns

Age
11 to 14
Challenge level
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How much of the square is coloured blue? How will the pattern continue?
Sieve of Eratosthenes
problem
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Sieve of Eratosthenes

Age
11 to 14
Challenge level
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Follow this recipe for sieving numbers and see what interesting patterns emerge.
Multiple Surprises
problem
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Multiple Surprises

Age
11 to 16
Challenge level
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Sequences of multiples keep cropping up...
Gabriel's Problem
problem
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Gabriel's Problem

Age
11 to 14
Challenge level
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Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?
Number Families
problem
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Number Families

Age
11 to 14
Challenge level
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How many different number families can you find?
Funny Factorisation
problem
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Funny Factorisation

Age
11 to 16
Challenge level
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Using the digits 1 to 9, the number 4396 can be written as the product of two numbers. Can you find the factors?
Take Three From Five
problem
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Take Three From Five

Age
11 to 16
Challenge level
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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
problem
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Stars

Age
11 to 14
Challenge level
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Can you work out what step size to take to ensure you visit all the dots on the circle?
Product Sudoku
problem
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Product Sudoku

Age
11 to 16
Challenge level
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The clues for this Sudoku are the product of the numbers in adjacent squares.
Route to infinity
problem
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Route to infinity

Age
11 to 14
Challenge level
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Can you describe this route to infinity? Where will the arrows take you next?
Power mad!
problem
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Power mad!

Age
11 to 14
Challenge level
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Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.
Alison's quilt
problem
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Alison's quilt

Age
11 to 14
Challenge level
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Nine squares are fitted together to form a rectangle. Can you find its dimensions?
Counting Factors
problem
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Counting Factors

Age
11 to 14
Challenge level
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Is there an efficient way to work out how many factors a large number has?
Shopping Basket
problem
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Shopping Basket

Age
11 to 16
Challenge level
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The items in the shopping basket add and multiply to give the same amount. What could their prices be?
Differences
problem
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Differences

Age
11 to 14
Challenge level
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Can you guarantee that, for any three numbers you choose, the product of their differences will always be an even number?
Beelines
problem
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Beelines

Age
14 to 16
Challenge level
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Is there a relationship between the coordinates of the endpoints of a line and the number of grid squares it crosses?
LCM Sudoku
problem
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LCM Sudoku

Age
14 to 16
Challenge level
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Here is a Sudoku with a difference! Use information about lowest common multiples to help you solve it.
Filling the gaps
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Filling the gaps

Age
14 to 16
Challenge level
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Which numbers can we write as a sum of square numbers?
Expenses
problem
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Expenses

Age
14 to 16
Challenge level
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What is the largest number which, when divided into 1905, 2587, 3951, 7020 and 8725 in turn, leaves the same remainder each time?
Latin Numbers
problem
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Latin Numbers

Age
14 to 16
Challenge level
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Can you create a Latin Square from multiples of a six digit number?