I love it when things click and my kids use the little tricks that I teach them.
For conversions we talk about small to big then you divide, big to small then you multiply.
I make them do hand motions, hands together small, stretch out big. Makes a division sign with your body.
Big to small they take their arms from stretched out (big) to a multiplication sign with their arms (small).
I love to see them doing the actions as they are working these problems.