This 2.5 x 2.5 yellow thermoplastic grid has white (odd) or (yellow) even numbers placed in each square
A great way to teach maths, but many other games can be played on this game
you can look at the Magical game card to see other ideas.
Ask for a - e and 1 - 5 to be placed on the outer of this marking to create a co-ordinates grid at a little cost more.