Nine color-coded squares in fractions of 1/2, 1/3, 1/4, 1/5, 1/6, 1/8, 1/10, 1/12 plus a whole. Made of dense foam, these squares are easy to handle and stay put nicely. Each of the 51 pieces are 0.5 centimeters thick. 51 pieces per pack, bundle of 6 packs, 306 pieces total