Working systematically

  • All-Variables Sudoku
    problem

    All-variables Sudoku

    Age
    11 to 18
    Challenge level
    filled star empty star empty star

    The challenge is to find the values of the variables if you are to solve this Sudoku.

  • Quadruple Clue Sudoku
    problem

    Quadruple clue Sudoku

    Age
    11 to 16
    Challenge level
    filled star empty star empty star

    Four numbers on an intersection that need to be placed in the surrounding cells. That is all you need to know to solve this sudoku.

  • Colour Islands Sudoku
    problem

    Colour islands Sudoku

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    An extra constraint means this Sudoku requires you to think in diagonals as well as horizontal and vertical lines and boxes of nine.

  • Another Quadruple Clue Sudoku
    problem

    Another quadruple clue Sudoku

    Age
    11 to 16
    Challenge level
    filled star empty star empty star

    This is a variation of sudoku which contains a set of special clue-numbers. Each set of 4 small digits stands for the numbers in the four cells of the grid adjacent to this set.

  • Loose Change
    problem

    Loose change

    Age
    11 to 14
    Challenge level
    filled star empty star empty star
    In how many ways can you give change for a ten pence piece?
  • Addition Equation Sudoku
    problem

    Addition equation Sudoku

    Age
    11 to 14
    Challenge level
    filled star empty star empty star

    You need to find the values of the stars before you can apply normal Sudoku rules.

  • LCM Sudoku II
    problem

    LCM Sudoku II

    Age
    11 to 18
    Challenge level
    filled star empty star empty star

    You are given the Lowest Common Multiples of sets of digits. Find the digits and then solve the Sudoku.

  • Colour Islands Sudoku 2
    problem

    Colour islands Sudoku 2

    Age
    11 to 18
    Challenge level
    filled star empty star empty star

    In this Sudoku, there are three coloured "islands" in the 9x9 grid. Within each "island" EVERY group of nine cells that form a 3x3 square must contain the numbers 1 through 9.

  • Rainstorm sudoku
    problem

    Rainstorm Sudoku

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

    Use the clues about the shaded areas to help solve this sudoku