Addition and subtraction

  • problem
    Favourite

    Two Primes Make One Square

    Age
    7 to 11
    Challenge level
    2 out of 3

    Can you make square numbers by adding two prime numbers together?

  • problem
    Favourite

    Oh! Harry!

    Age
    7 to 11
    Challenge level
    2 out of 3

    A group of children are using measuring cylinders but they lose the labels. Can you help relabel them?

  • problem
    Favourite

    This Pied Piper of Hamelin

    Age
    7 to 11
    Challenge level
    2 out of 3

    How many people and rats could there be if you know how many legs there are altogether?

  • problem
    Favourite

    How Much Did It Cost?

    Age
    7 to 11
    Challenge level
    2 out of 3

    Use your logical thinking skills to deduce how much Dan's crisps and ice cream cost altogether.

  • Six Ten Total
    problem
    Favourite

    Six Ten Total

    Age
    7 to 11
    Challenge level
    2 out of 3

    This challenge combines addition, multiplication, perseverance and even proof.

  • Six Numbered Cubes
    problem
    Favourite

    Six Numbered Cubes

    Age
    7 to 11
    Challenge level
    2 out of 3

    This task combines spatial awareness with addition and multiplication.

  • Digit Addition
    problem
    Favourite

    Digit Addition

    Age
    7 to 11
    Challenge level
    2 out of 3

    Try out this number trick. What happens with different starting numbers? What do you notice?

  • 4 Dom
    problem
    Favourite

    4 Dom

    Age
    7 to 11
    Challenge level
    3 out of 3

    Use these four dominoes to make a square that has the same number of dots on each side.

  • A gold balloon of the number 4.
    problem
    Favourite

    Four Goodness' Sake

    Age
    7 to 11
    Challenge level
    3 out of 3

    Use 4 four times in a calculation. What answers can you get?

  • Two switches, one set to 'on' (represented by 1) and one set to 'off' (represented by 0).
    problem
    Favourite

    Binary Thinking

    Age
    7 to 11
    Challenge level
    3 out of 3

    In the binary number system, we only use the digits 0 and 1. What can you discover about this system?