Combinations

  • problem
    Favourite

    Sweets in a Box

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

    How many different shaped boxes can you design for 36 sweets in one layer? Can you arrange the sweets so that no sweets of the same colour are next to each other in any direction?

  • Buying a Balloon
    problem
    Favourite

    Buying a Balloon

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

    Lolla bought a balloon at the circus. She gave the clown six coins to pay for it. What could Lolla have paid for the balloon?

  • Making Cuboids
    problem
    Favourite

    Making Cuboids

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

    Let's say you can only use two different lengths - 2 units and 4 units. Using just these 2 lengths as the edges how many different cuboids can you make?

  • Prison Cells
    problem
    Favourite

    Prison Cells

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

    There are 78 prisoners in a square cell block of twelve cells. The clever prison warder arranged them so there were 25 along each wall of the prison block. How did he do it?

  • Finding Fifteen
    problem
    Favourite

    Finding Fifteen

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

    Tim had nine cards each with a different number from 1 to 9 on it. How could he have put them into three piles so that the total in each pile was 15?

  • problem
    Favourite

    The Twelve Pointed Star Game

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

    Have a go at this game which involves throwing two dice and adding their totals. Where should you place your counters to be more likely to win?

  • Sealed Solution
    problem
    Favourite

    Sealed Solution

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

    Ten cards are put into five envelopes so that there are two cards in each envelope. The sum of the numbers inside it is written on each envelope. What numbers could be inside the envelopes?

  • Elevenses
    problem
    Favourite

    Elevenses

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

    How many pairs of numbers can you find that add up to a multiple of 11? Do you notice anything interesting about your results?

  • 1 Step 2 Step
    problem
    Favourite

    1 Step 2 Step

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

    Liam's house has a staircase with 12 steps. He can go down the steps one at a time or two at time. In how many different ways can Liam go down the 12 steps?

  • Six times five
    problem
    Favourite

    Six Times Five

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    How many six digit numbers are there which DO NOT contain a 5?