Name the property user in each step

2.75+3.5+4.25+1.5

I'm not sure what the "user" part means, and properties in math are general rules that are used in calculations.

If you need the property for each step, it is the commutative property of addition for every step, because it is all addition. (The commutative property of addition states that no matter the order in which numbers are added, they combine to the same result.)

If you mean something else, let me know.