Addition and subtraction

  • Summing Consecutive Numbers
    problem

    Summing consecutive numbers

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    15 = 7 + 8 and 10 = 1 + 2 + 3 + 4. Can you say which numbers can be expressed as the sum of two or more consecutive integers?

  • Magic Letters
    problem

    Magic letters

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Charlie has made a Magic V. Can you use his example to make some more? And how about Magic Ls, Ns and Ws?

  • Strange Bank Account
    problem

    Strange bank account

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Imagine a very strange bank account where you are only allowed to do two things...

  • Up, down, flying around
    game
    Favourite

    Up, down, flying around

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Play this game to learn about adding and subtracting positive and negative numbers

  • Number Daisy
    problem

    Number daisy

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Can you find six numbers to go in the daisy from which you can make all the numbers from 1 to a number bigger than 25?

  • Cryptarithms
    problem

    Cryptarithms

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    Can you crack these cryptarithms?

  • Add to 200
    problem

    Add to 200

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    By selecting digits for an addition grid, what targets can you make?

  • Forwards Add Backwards
    problem

    Forwards add backwards

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    What happens when you add a three digit number to its reverse?

  • Making a difference
    problem

    Making a difference

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    How many different differences can you make?

  • 3388
    problem

    3388

    Age
    11 to 14
    Challenge level
    filled star filled star empty star

    Using some or all of the operations of addition, subtraction, multiplication and division and using the digits 3, 3, 8 and 8 each once and only once make an expression equal to 24.