KenKen Puzzle Number 31 - 6x6 Normal Difficulty

This is the first of a series of normal difficulty 6x6 puzzles from the free Mathdoku App.  For 6x6
problems we use the numbers 1 thru 6 and each row or column will total 21.

These puzzles often involve factoring numbers down and seeing how many possibilities there are.  The solution for this puzzle includes extended explanations for reducing the factors to a set of possibilities.

The Solution to Puzzle 31: 6x6 Normal Difficulty