The Subtraction Equations and Differences Box (C 111) is a language-of-math material that supports children in reading, sorting, and internalizing written subtraction equations by matching them to their correct differences. Designed for the lower elementary child who has moved beyond concrete bead work and is building fluency with abstract operations, it reinforces the connection between symbolic notation and arithmetic fact recall. It works especially well as an independent follow-up activity after group lessons on the subtraction facts.