What property is shown?
5 + (8 + 7) = (5 + 8) + 7
I think its the commutative property of addition but I'm not sure...
Associative
http://www.mathwarehouse.com/dictionary/A-words/definition-of-associative-property.php
Actually, the property shown in the equation is the associative property of addition, not the commutative property of addition.
The commutative property of addition states that you can change the order of the numbers being added without changing the result. For example, if you have the equation 5 + 3, you can switch the order to 3 + 5 and still get the same result of 8.
On the other hand, the associative property of addition states that the way you group the numbers being added does not affect the result. In this case, the equation shows that regardless of whether we first add 8 and 7 or first add 5 and 8, the total sum will be the same. The parentheses are indicating how the numbers are grouped, and by rearranging the grouping, we are showing the associative property of addition.
To check if an equation demonstrates a certain property, it is important to understand the definitions of the properties and find examples that match them. In this case, the equation exhibits the associative property because it shows that regardless of the grouping of the numbers being added, the total sum remains the same.