A different and fun way to practice rational number facts with INTEGERS (adding facts within +/-100). Sum squares provide the answers, students need to fill in all 4 boxes in the Sum Square to produce the correct sums across each row and down each column! It's a fantastic way to also practice addition fact fluency with positive and negative integers. The download comes with 4 practice worksheets (36 unique puzzles in total!), 1 "make your own" Sum Square worksheet and complete solutions pages.ID