Is Mathematics Really What You Think?

List of mathematics competitions

The complete list of mathematics competitions includes more than 400 links to international and national competitions.

http://en.wikipedia.org/wiki/List_of_mathematics_competitions

Have Brain? Use it!

Find the area of the rectangle if the numbers show the areas of the corresponding triangles.

Find the area of the shape.

How many squares of all different sizes are on a chessboard?