Addition and Subtraction – Inverse Operations (Equations) . Concept/s in Focus: 👉 Addition is joining quantities (parts) together to make a total (part part = total) 👉 Subtraction is separating a total into parts or taking one part away from the total leaving a part (Total – Part = Part) 👉 Addition and subtraction are inverse operations. The action of one will undo the other. Addition joins parts to make a total and subtraction separates a total into parts. 👉 Addition and subtraction are inv