Today we worked on why you can use addition to check subtraction. Gracyn completed subtraction problems and then added to check her answer. We focused on the concept of subtracting one part from the whole to get the difference or the other part. Then, the two parts added together get the whole. Gracyn really understood the logic behind this when she subtracted incorrectly and then added to find the numbers didn't correlate. Together, Gracyn and I played jellyfish subtract. We took turns completing subtraction of 10 problems using numbers up to 90. If answered correctly, a square was colored. The longest line of colored squares won the game.