Question

Riley had to add this group of numbers (56 + 47 + 53), but he wanted to add them as quickly and as easily as possible. Here is how he decided to add the numbers: 56 + 47 + 53 = 56 + (47 + 53) = 56 + 100 = 156. Which number property allowed him to add the numbers in this way?

Answer 1

156

Explanation:

first add 47 and 53, then add 100 and 56, then you get your answer.