hom and tensor exactness
Let us consider $A$-modules. The $\text{Hom}(N,-)$ functor is left exact, and the functor $-\otimes_A N$ is right exact.
Let us consider $A$-modules. The $\text{Hom}(N,-)$ functor is left exact, and the functor $-\otimes_A N$ is right exact.