*Clearance Price – Final Sale – Limited Quantities Available* Develops skills in mental math, decomposing numbers, algebraic thinking, and word problems. Each of these self-checking puzzles has 7 pieces; 1 hexagon piece displaying a number from 1-20 and 6 trapezoid pieces that display equivalent addition and subtraction problems. The set includes 20 puzzles, plus a self-check container that students flip over for added fun! 140 pieces total, plus and additional 40 interchangeable pieces in French.