You do not necessarily need to purchase a specific curriculum for kindergarten math. To recognize shapes and practice matching, you can either use ready-made worksheets or workbooks, or make some of your own.
If you make your own, you can just draw three circles on a page and then 2-5 triangles on a page, and ask the child to match each circle with a triangle by drawing a line from shape to shape. Vary the shapes and the amounts. Sometimes the amounts should be equal, sometimes not.