Thinking Mathematically (6th Edition)

The contrapositive of $p\rightarrow q$ is $\sim q\rightarrow \sim p$. The converse of $p\rightarrow q$ is $q \rightarrow p$. The inverse of $p\rightarrow q$ is $\sim p\rightarrow \sim q$. Hence here the converse is: If today is not a holiday, then I am in class. The inverse: If I am not in class, then today is a holiday. The contrapositive: If today is a holiday, then I am not in class.