Associative property addition is quite a different way of addition. There are three digits involved in these types of questions. According to the property of addition, the numbers grouped for the sum. Two numbers have been grouped together in the set of three digits on one side and on the other side same numbers have been given and the grouping for addition is different. Answers have been the same after the addition of both sides. For example : Associative property for Addition : a + (b + c) = (a + b) + c. Substitute values for a=1, b=2, c=3 for addition. After substituting the values : 1 + (2 + 3) = (1 + 2) + 3 = 6. The grouping on both of the sides is different and the answers are the same.