Question

Which property is illustrated by the following statement?
AB=CD, so AD+DE = CD+DE

Answer 1

I assume you meant AB + DE, NOT AD + DE

The principle used is the Addition Principle of Equality (as you are adding DE to both sides of the equation)

Answer 2

Yes I did sorry! Also thanks I assumed that's what it was, but wanted to be sure.

Answer 3

You're very welcome.