Explaining Division of Fractions

Division of fractions is generally taught in elementary grades by the rule, "invert and multiply." But why does this work? It can be explained formally by the field axioms, but that doesn't help demystify the rule for 4th or 5th graders. A while back I was asked why this rule works and I realized it was never explained to me as a student. After some thought, here is what I came up with. I hope it helps. ... https://www.youtube.com/watch?v=jttBH_93czc