Explaining, convincing and proving

  • Weekly Lies
    problem

    Weekly Lies

    Age
    11 to 14
    Challenge level
    1 out of 3

    Mr Ross tells truths or lies depending on the day of the week. Can you catch him out?

  • Small pepper seedlings in turquoise pots.
    problem

    Distinct Diagonals

    Age
    11 to 14
    Challenge level
    1 out of 3

    Weekly Problem 21 - 2010
    How many diagonals can you draw on this square...

  • Kept Apart
    problem

    Kept Apart

    Age
    11 to 14
    Challenge level
    1 out of 3

    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 tomato seedlings in yellow pots.
    problem

    Would You Like a Jelly Baby?

    Age
    11 to 14
    Challenge level
    1 out of 3

    What is the smallest number of jelly babies Tom must take, to be certain that he gets at least one of each flavour?

  • Small tomato seedlings in pink pots.
    problem

    Multiplication Magic Square

    Age
    11 to 14
    Challenge level
    1 out of 3

    Weekly Problem 32 - 2015
    Can you work out the missing numbers in this multiplication magic square?

  • Small tomato seedlings in pink pots.
    problem

    Down and Along

    Age
    11 to 14
    Challenge level
    1 out of 3

    Can you work out the values of J, M and C in this sum?

  • Small pepper seedlings in turquoise pots.
    problem

    Other Side

    Age
    11 to 14
    Challenge level
    1 out of 3

    Weekly Problem 8 - 2016
    Can you work out the size of the angles in a quadrilateral?

  • Small pepper seedlings in turquoise pots.
    problem

    Equilateral Pair

    Age
    11 to 14
    Challenge level
    1 out of 3

    Weekly Problem 39 - 2016
    In the diagram, VWX and XYZ are congruent equilateral triangles. What is the size of angle VWY?

  • Small tomato seedlings in pink pots.
    problem

    What's on the Back?

    Age
    11 to 14
    Challenge level
    1 out of 3

    Four cards have a number on one side and a phrase on the back. On each card, the number does not have the property described on the back. What do the four cards have on them?

  • Small pepper seedlings in turquoise pots.
    problem

    Shared Vertex

    Age
    11 to 14
    Challenge level
    1 out of 3

    Weekly Problem 38 - 2017
    In the diagram, what is the value of $x$?