Working systematically

  • 9 Weights
    problem

    9 Weights

    Age
    11 to 14
    Challenge level

    You have been given nine weights, one of which is slightly heavier than the rest. Can you work out which weight is heavier in just two weighings of the balance?

  • Small tomato seedlings in pink pots.
    problem

    Loose Change

    Age
    11 to 14
    Challenge level

    In how many ways can you give change for a ten pence piece?

  • Multiples Sudoku
    problem

    Multiples Sudoku

    Age
    11 to 14
    Challenge level

    Each clue in this Sudoku is the product of the two numbers in adjacent cells.

  • Island Hopping
    problem

    Island Hopping

    Age
    11 to 14
    Challenge level

    What is the smallest number of ferry trips that Neda needs to take to visit all four islands and return to the mainland?

  • Small pepper seedlings in turquoise pots.
    problem

    Grid Without Lines

    Age
    11 to 14
    Challenge level

    Can you remove the least number of points from this diagram, so no three of the remaining points are in a straight line?

  • Kept Apart
    problem

    Kept Apart

    Age
    11 to 14
    Challenge level

    The squares of this grid contain one of the letters P, Q, R and S. Can you complete this square so that touching squares do not contain the same letter? How many possibilities are there?

  • Small pepper seedlings in orange pots.
    problem

    Fruit Line-Up

    Age
    11 to 14
    Challenge level

    This grocer wants to arrange his fruit in a particular order, can you help him?

  • Colourful Tiles
    problem

    Colourful Tiles

    Age
    11 to 14
    Challenge level

    Weekly Problem 21 - 2011
    How many ways can you paint this wall with four different colours?

  • Mini-Sudoku
    problem

    Mini-Sudoku

    Age
    11 to 14
    Challenge level

    How many ways are there of completing the mini-sudoku?

Displaying 481 - 490 of 586