Factors, Multiples and Primes: Age 11-16

This is part of ourĀ Secondary Curriculum collection of favourite rich tasks arranged by topic.

  • Dozens
    problem
    Favourite

    Dozens

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

  • Factors and Multiples Game
    game
    Favourite

    Factors and Multiples Game

    Age
    7 to 16
    Challenge level
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    A game in which players take it in turns to choose a number. Can you block your opponent?

  • Xavi's T-shirt
    problem
    Favourite

    Xavi's T-Shirt

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

  • An American flag waving in the wind.
    problem
    Favourite

    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...

  • 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?
    problem
    Favourite

    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. 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
    Favourite

    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.

  • 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
    Favourite

    Number Families

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

  • Counting Factors
    problem
    Favourite

    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?

  • 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?

  • Factors and Multiples Puzzle
    problem
    Favourite

    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?

  • Route to infinity
    problem
    Favourite

    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.

  • A blue patchwork quilt draped over a white sofa.
    problem
    Favourite

    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?

  • Four playing cards on top of each other. Each card shows a different ace.
    problem
    Favourite

    Snappy Statements

    Age
    11 to 14
    Challenge level
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    Use properties of numbers to work out whether you can satisfy all these statements at the same time.

  • 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?

  • Divisibility Tests
    article

    Divisibility Tests

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

  • 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...

  • 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?

  • Product Sudoku
    problem
    Favourite

    Product Sudoku

    Age
    11 to 16
    Challenge level
    filled star filled star empty star

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

  • problem
    Favourite

    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?

  • Beelines
    problem
    Favourite

    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?

  • Expenses
    problem
    Favourite

    Expenses

    Age
    14 to 16
    Challenge level
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    What is the largest number which, when divided into these five numbers in turn, leaves the same remainder each time?

  • Filling the gaps
    problem
    Favourite

    Filling the Gaps

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

  • 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?

  • 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.