Working systematically

  • Rainstorm sudoku
    problem

    Rainstorm Sudoku

    Age
    14 to 16
    Challenge level
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    Use the clues about the shaded areas to help solve this sudoku

  • Adjacent Additions
    problem

    Adjacent Additions

    Age
    14 to 16
    Challenge level
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    In a 7-digit numerical code, each group of four consecutive digits adds to 16, and each group of five consecutive digits adds to 19. What is the sum of all 7 digits?

  • End of a Prime
    problem

    End of a Prime

    Age
    14 to 16
    Challenge level
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    I made a list of every number that is the units digit of at least one prime number. How many digits appear in the list?

  • Threes and Fours
    problem

    Threes and Fours

    Age
    14 to 16
    Challenge level
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    What is the smallest integer where every digit is a 3 or a 4 and it is divisible by both 3 and 4?

  • Quadratic Matching
    problem

    Quadratic Matching

    Age
    14 to 16
    Challenge level
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    Can you match each graph to one of the statements?

  • Olympic Magic
    problem

    Olympic Magic

    Age
    14 to 16
    Challenge level
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    in how many ways can you place the numbers 1, 2, 3 … 9 in the nine regions of the Olympic Emblem (5 overlapping circles) so that the amount in each ring is the same?

  • Magic W
    problem

    Magic W

    Age
    14 to 16
    Challenge level
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    Find all the ways of placing the numbers 1 to 9 on a W shape, with 3 numbers on each leg, so that each set of 3 numbers has the same total.

  • Tetrahedra Tester
    problem

    Tetrahedra Tester

    Age
    14 to 16
    Challenge level
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    An irregular tetrahedron is composed of four different triangles. Can such a tetrahedron be constructed where the side lengths are 4, 5, 6, 7, 8 and 9 units of length?

  • Twin Line-Swapping Sudoku
    problem

    Twin Line-Swapping Sudoku

    Age
    14 to 16
    Challenge level
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    A pair of Sudoku puzzles that together lead to a complete solution.

  • Facial Sums
    problem

    Facial Sums

    Age
    14 to 16
    Challenge level
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    Can you make the numbers around each face of this solid add up to the same total?