Answer: Associative Property of Addition
Step-by-step explanation:
Associative Property of Addition says that we can add by avoiding how the expressions are grouped by using parenthesis .
Let a, b, c be two expressions, then , we have
, for any a, b and c.
The given equation : 
By considering the definition of Associative Property of Addition , we can say that the property use to illustrate the given equation is Associative Property of Addition .