Math is much more fun when it's interactive. Clothespins are a wonderful manipulative because they not only let a child experience math with hands-on activities but they also help to strengthen those little fingers each time the pin is pressed open! Duel learning!
A great clothespin activity is geometry = creating shapes!
Kids can clip them together to make squares, triangles, pentagons, etc.
It's easy to show kids that if you add one more clothespin to a triangle, you can build a square.
Add one more to only one side of a square and you have a trapaziod!
And if you create both large and small shapes, kids can practice the concept of smaller/larger or put them in size order.
Pull out a ruler and older kids can measure the sides to find the shapes' perimeter or area too!