9514 1404 393
Answer:
properties of addition let you add, subtract, or rearrange the terms of a sum as may be needed
Explanation:
Properties of addition let you rearrange a sum to make addition easier to do or to check mentally. They also let you "undo" addition or subtraction in the process of solving algebra problems. And, they let you add terms or constants that may make it easier to rearrange expressions, as in "completing the square."