Working systematically

Players take it in turns to choose a dot on the grid. The winner is the first to have four dots that can be joined to form a parallelogram.

Can you solve the clues to find out who's who on the friendship graph?

Using the digits 1 to 9, the number 4396 can be written as the product of two numbers. Can you find the factors?

Can you recreate these designs? What are the basic units? What movement is required between each unit? Some elegant use of procedures will help - variables not essential.

Just four procedures were used to produce a design. How was it done? Can you be systematic and elegant so that someone can follow your logic?

A Sudoku with a twist.

A Sudoku with clues as ratios.

The clues for this Sudoku are the product of the numbers in adjacent squares.

Mr McGregor has a magic potting shed. Overnight, the number of plants in it doubles. He'd like to put the same number of plants in each of three gardens, planting one garden each day. Can he do it?

This Sudoku, based on differences. Using the one clue number can you find the solution?