Tangrams are objects that children can use to experiment with geometric concepts. Children are concrete learners until the age of 12. Using manipulatives such as tangrams is the best way to teach math to children from preschool to age 11.
Lots of mathematical concepts are explored through the play with tangrams: congruency, symmetry, area, perimeter, and geometric shapes.
There are 15 puzzles that are put on 3 different levels for a total of 45 puzzles.
This app is a great tool for math.