Exercise 5.
Let \(a\text{,}\) \(b\text{,}\) \(c\text{,}\) and \(n\) be integers. Prove that if \(a \equiv b \pmod{n}\) and \(c \equiv d \pmod{n}\text{,}\) then \(a-c \equiv b-d \pmod{n}\text{.}\)
Let \(a\text{,}\) \(b\text{,}\) \(c\text{,}\) and \(n\) be integers. Prove that if \(a \equiv b \pmod{n}\) and \(c \equiv d \pmod{n}\text{,}\) then \(a-c \equiv b-d \pmod{n}\text{.}\)