#### Answer

associative

#### Work Step by Step

Since $n+(x+a)=(n+x)+a$, we say that addition is associative.
The associative property states that $a+(b+c)=(a+b)+c$, where $a$, $b$, and $c$ are real numbers. This property tells us that the sum of 3 numbers is the same, regardless of the grouping of the numbers.