1.Prove the every group G of order 4 is isomorphic to either Z4 or 4-group V,that is {1 (1,2)(3,4) (1,3)(2,4) (1,4)(2,3)}
2.If G is a group with $|G|\leq 5$ then G is abelian.
I have learned independently the chapter 1 of the book An introduction to group theory by Joseph Rotman . And can understand it ,can solve many exercises in it.I can understand the proofs in chapter 2 , however I totally don't have any intuition of the exercises. Does any suggestion?