Visualising and representing

  • Soma - So Good
    problem

    Soma - so good

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    Can you mentally fit the 7 SOMA pieces together to make a cube? Can you do it in more than one way?
  • Around and Back
    problem

    Around and back

    Age
    14 to 16
    Challenge level
    filled star filled star filled star
    A cyclist and a runner start off simultaneously around a race track each going at a constant speed. The cyclist goes all the way around and then catches up with the runner. He then instantly turns around and heads back to the starting point where he meets the runner who is just finishing his first circuit. Find the ratio of their speeds.
  • AMGM
    problem

    AMGM

    Age
    14 to 16
    Challenge level
    filled star filled star filled star

    Can you use the diagram to prove the AM-GM inequality?

  • Take Ten
    problem

    Take ten

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    Is it possible to remove ten unit cubes from a 3 by 3 by 3 cube so that the surface area of the remaining solid is the same as the surface area of the original?
  • Framed
    problem

    Framed

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    Seven small rectangular pictures have one inch wide frames. The frames are removed and the pictures are fitted together like a jigsaw to make a rectangle of length 12 inches. Find the dimensions of the pictures.
  • Getting an angle
    problem

    Getting an angle

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    How can you make an angle of 60 degrees by folding a sheet of paper twice?
  • Cutting a Cube
    problem

    Cutting a cube

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    A half-cube is cut into two pieces by a plane through the long diagonal and at right angles to it. Can you draw a net of these pieces? Are they identical?
  • Cubic Conundrum
    problem

    Cubic conundrum

    Age
    7 to 16
    Challenge level
    filled star filled star filled star
    Which of the following cubes can be made from these nets?
  • Cubist Cuts
    problem

    Cubist cuts

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    A 3x3x3 cube may be reduced to unit cubes in six saw cuts. If after every cut you can rearrange the pieces before cutting straight through, can you do it in fewer?
  • Rati-o
    problem

    Rati-o

    Age
    11 to 14
    Challenge level
    filled star filled star filled star
    Points P, Q, R and S each divide the sides AB, BC, CD and DA respectively in the ratio of 2 : 1. Join the points. What is the area of the parallelogram PQRS in relation to the original rectangle?