As kids put together our skill-building sun puzzles, they boost addition fluency with decomposing numbers—in a concrete, visual way! Each self-correcting puzzle features a number from 4 to 20, plus 5 equation pieces that each show an addition problem. Kids just match the number in the sun’s center to the corresponding equations—developing addition fluency with instant reinforcement! Set includes 17 puzzles divided into 4 skill levels that gradually progress in difficulty. Puzzles measure 6".