Factors, Multiples and Primes: Age 11-16
This is part of ourĀ Secondary Curriculum collection of favourite rich tasks arranged by topic.
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gameFavouriteFactors and Multiples Game
A game in which players take it in turns to choose a number. Can you block your opponent?
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problemFavouriteAmerican 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...
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problemFavouriteMultiples Sudoku
Each clue in this Sudoku is the product of the two numbers in adjacent cells.
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problemFavouriteHow Much Can We Spend?
A country has decided to have just two different coins. Which totals can be made? Is there a largest total that cannot be made? How do you know?
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problemFavouriteDiminishing Returns
How much of the square is coloured blue? How will the pattern continue?
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problemFavouriteSieve of Eratosthenes
Follow this recipe for sieving numbers and see what interesting patterns emerge.
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problemFavouriteGabriel's Problem
Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?
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problemFavouriteCounting Factors
Is there an efficient way to work out how many factors a large number has?
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problemFavouriteStars
Can you work out what step size to take to ensure you visit all the dots on the circle?
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problemFavouriteFactors and Multiples Puzzle
Using your knowledge of the properties of numbers, can you fill all the squares on the board?
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problemFavouriteRoute to Infinity
Can you describe this route to infinity? Where will the arrows take you next?
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problemFavouritePower Mad!
Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.
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problemFavouriteAlison's Quilt
Nine squares are fitted together to form a rectangle. Can you find its dimensions?
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problemFavouriteSnappy Statements
Use properties of numbers to work out whether you can satisfy all these statements at the same time.
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problemFavouriteDifferences
Can you guarantee that, for any three numbers you choose, the product of their differences will always be an even number?
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articleDivisibility Tests
This article explains various divisibility rules and why they work. An article to read with pencil and paper handy.
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problemFavouriteFunny Factorisation
Using the digits 1 to 9, the number 4396 can be written as the product of two numbers. Can you find the factors?
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problemFavouriteTake 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?
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problemFavouriteProduct Sudoku
The clues for this Sudoku are the product of the numbers in adjacent squares.
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problemFavouriteShopping Basket
The items in the shopping basket add and multiply to give the same amount. What could their prices be?
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problemFavouriteBeelines
Is there a relationship between the coordinates of the endpoints of a line and the number of grid squares it crosses?
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problemFavouriteExpenses
What is the largest number which, when divided into these five numbers in turn, leaves the same remainder each time?
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problemFavouriteLCM Sudoku
Here is a Sudoku with a difference! Use information about lowest common multiples to help you solve it.