The property of addition that has been applied in this case is the commutative property. The commutative property of addition states that changing the order of the addends does not change the sum. In other words, when adding two numbers, you can switch the order of the numbers and still get the same result. So, in the given expression: 5 + 8 = 8 + 5, the commutative property has been applied by switching the order of the addends 5 and 8.
