Which expression demonstrates the associative property of addition?

Which expression demonstrates the associative property of addition?

• A. a + b = b + a
• B. Ax + By = C
• C. (a + b) + c = a + (b + c)
• D. a(b + c) = ab + ac

Answer: (C)

Associative property of addition means the way you group numbers when adding doesn’t change the total. You can add a and b first, then add c, or add b and c first, then add a, and you’ll end up with the same sum. The expression that shows these two groupings giving the same result is (a + b) + c = a + (b + c). For example, (2 + 3) + 4 = 5 + 4 = 9, and 2 + (3 + 4) = 2 + 7 = 9, which illustrates the idea. The other forms involve different concepts: swapping order of addends is the commutative property (a + b = b + a), and a(b + c) = ab + ac is the distributive property.

Associative property of addition means the way you group numbers when adding doesn’t change the total. You can add a and b first, then add c, or add b and c first, then add a, and you’ll end up with the same sum. The expression that shows these two groupings giving the same result is (a + b) + c = a + (b + c).

For example, (2 + 3) + 4 = 5 + 4 = 9, and 2 + (3 + 4) = 2 + 7 = 9, which illustrates the idea.

The other forms involve different concepts: swapping order of addends is the commutative property (a + b = b + a), and a(b + c) = ab + ac is the distributive property.