Combinations

  • Add 3 Dice
    problem

    Add 3 dice

    Age
    7 to 11
    Challenge level
    filled star filled star empty star
    Three dice are placed in a row. Find a way to turn each one so that the three numbers on top of the dice total the same as the three numbers on the front of the dice. Can you find all the ways to do this?
  • Cross-Country Race
    problem

    Cross-country race

    Age
    14 to 16
    Challenge level
    filled star filled star empty star
    Eight children enter the autumn cross-country race at school. How many possible ways could they come in at first, second and third places?
  • Clocked
    problem

    Clocked

    Age
    11 to 14
    Challenge level
    filled star filled star empty star
    Is it possible to rearrange the numbers 1,2......12 around a clock face in such a way that every two numbers in adjacent positions differ by any of 3, 4 or 5 hours?
  • Semaphore Signals
    problem

    Semaphore signals

    Age
    7 to 11
    Challenge level
    filled star filled star empty star
    Semaphore is a way to signal the alphabet using two flags. You might want to send a message that contains more than just letters. How many other symbols could you send using this code?
  • Brailler
    problem

    Brailler

    Age
    11 to 14
    Challenge level
    filled star filled star empty star
    The machine I use to produce Braille messages is faulty and one of the pins that makes a raised dot is not working. I typed a short message in Braille. Can you work out what it really says?
  • Move a Match
    problem

    Move a match

    Age
    7 to 11
    Challenge level
    filled star filled star empty star
    How can you arrange these 10 matches in four piles so that when you move one match from three of the piles into the fourth, you end up with the same arrangement?
  • Painting Cubes
    problem

    Painting cubes

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    Imagine you have six different colours of paint. You paint a cube using a different colour for each of the six faces. How many different cubes can be painted using the same set of six colours?
  • Scratch Cards
    problem

    Scratch cards

    Age
    14 to 16
    Challenge level
    filled star filled star filled star
    To win on a scratch card you have to uncover three numbers that add up to more than fifteen. What is the probability of winning a prize?
  • Factoring a million
    problem

    Factoring a million

    Age
    14 to 16
    Challenge level
    filled star filled star filled star
    In how many ways can the number 1 000 000 be expressed as the product of three positive integers?
  • Domino tetrads
    problem

    Domino tetrads

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    Is it possible to use all 28 dominoes arranging them in squares of four? What patterns can you see in the solution(s)?