Hunt for shapes around the house to build your child's math skills.
Show your child a rectangle (or triangle, circle, etc.), describe its shape, and then go on a scavenger hunt to find other rectangles in the house (a cereal box, a table top, etc.).
Do the same with other shapes. You can make this game more advanced as your child gets older by adding in three-dimensional shape vocabulary, such as spheres, cubes, pyramids, and so on.