The property a×1=a seems so basic but believe it or not, it helps explain why "keep change flip" works. Here's how:

Can we not use the phrase "Keep Change Flip"?

I personally don't use it in the classroom but that's unfortunately how a lot of people outside of my own classroom sees it.

How about instead of teaching gimmicks like “keep change flip” we demonstrate why dividing by 2 is the same as multiplying by 1/2 etc then extrapolate a generalization?

I personally don't say "keep change flip" in the classroom but unfortunately it's the most common way people know it. I show it through visuals with the partitive model.

Does anyone else find this argument circular? In order to show how keep-change-flip works, we need to multiply 2/5 by 3/4's reciprocal (e.g. 1/(3/4)) in order to create a complex fraction.

Love this!!! So clear

@JTaggart25

I think I understand your reasoning here. But aren’t you really showing that a*(1/a) = 1 which is another way of stating your property; multiplicative identity. It would seem that is lost in your explanation.

I’m getting to division of fractions with my 6th graders. And while they won’t understand the complex fraction structure, this video will make teaching keep change flip a whole lot easier and make more sense. Thank you!

Oh yes, I do this on the number line for the measurement model in my class.