problem
Favourite
Square subtraction
Look at what happens when you take a number, square it and subtract your answer. What kind of number do you get? Can you prove it?
The discs for this game are kept in a flat square box with a square hole for each. Use the information to find out how many discs of each colour there are in the box.
Imagine a pyramid which is built in square layers of small cubes. If we number the cubes from the top, starting with 1, can you picture which cubes are directly below this first cube?