Answer: Associative Property of Addition
Step-by-step explanation: The problem (6 + 7) + 8 = 6 + (7 + 8)
demonstrates the associative property of addition.
Notice that the addends, or the number we're adding,
are the same on both sides of the equals sign, 6 + 7 + 8.
The associative property of addition tells us that when we're adding more
than two numbers, the grouping of addends does not change the sum.
For example here, (6 + 7) gives us 13, and 14 + 8 gives us 21.
On the right side, (7 + 8) gives us 15, and 6 + 15 gives us 21.
So the sum is the same, regardless of which way we group the addends.