Practice addition and subtraction fluency with these equivalent operation puzzles. Develops skills in mental math, decomposing numbers, algebraic thinking, and word problems. Each of these self-checking puzzles has 7 pieces - a hexagon piece displaying a number from 1-20, and 6 trapezoid pieces that display equivalent addition and subtraction problems. The set includes 20 puzzles; an orange set from 1-10 and a blue set from 11-20, plus a self-check container that students flip over for added fun! 140 pieces total, plus and additional 40 interchangeable pieces in French. Ages 3+. Grades 1+