Sort the houses in my street into different groups. Can you do it in any other ways?...

This video of Charlie and Liz solving a 6 by 6 mathdoku may give you ideas for strategies to try....

How many moves does it take to swap over some red and blue frogs? Do you have a method?...

Can you find a reliable strategy for choosing coordinates that will locate the treasure in the minimum number of guesses?...

Can you use the clues to complete these 6 by 6 Mathematical Sudokus?...

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

Can you use the clues to complete these 4 by 4 Mathematical Sudokus?...

Can you use the clues to complete these 3 by 3 Mathematical Sudokus?...

Three semi-circles have a common diameter, each touches the other two and two lie inside the biggest one. What is the radius of the circle that touches all three semi-circles?...

In how many different ways can you break up a stick of seven interlocking cubes? Now try with a stick of eight cubes and a stick of six cubes. What do you notice?...