Working systematically

On the graph there are 28 marked points. These points all mark the vertices (corners) of eight hidden squares. Can you find the eight hidden squares?

Can you make doughnuts by matching these fractions, decimals and percentages?

These points all mark the vertices (corners) of ten hidden squares. Can you find the 10 hidden squares?

Solve this Sudoku puzzle whose clues are in the form of sums of the numbers which should appear in diagonal opposite cells.

A Sudoku with clues given as sums of entries.

In this interactivity each fruit has a hidden value. Can you deduce what each one is worth?

Can you use the clues to complete these 5 by 5 Mathematical Sudokus?

How many solutions can you find to this sum? Each of the different letters stands for a different number.

Take an equilateral triangle and cut it into smaller pieces. What can you do with them?

Choose some fractions and add them together. Can you get close to 1?