What is commutative property of addition?

The commutative property of addition says we can change the order of the terms and the result is the same.
Thus a+b=b+a.
This is one of the field properties of the real numbers.

This site explains the commutative property of addition.

(Broken Link Removed)

I am having trouble "working out" 5th grade problems for" properties of addition" can anyone please help!