Identity Property of Addition

Consider a number a. By the Reflexive Property of Equality, a is equal to itself. a=a Let b be another number. If b is added to and subtracted from the left-hand side of the above equation, the equality still holds true. a=a ⇔ a+b-b=a Finally, b-b is equal to 0. a+b-b=a ⇔ a+0=a ✓ It has been shown that a+0=a. By the Commutative Property of Addition, 0+a is also equal to a.