Just to be totally clear, I wouldn't bring this video inside fifty feet of a classroom. I'm not recommending you use this video in a classroom. I'm recommending that when you see math in the world around you that you get in the practice of doing something about it — especially, that you turn it into a question.
Don't know how to do the black box and the censor beep? Just pause the video right before she answers her own question. Point being, the more you habituate this practice — even on lessons like this one that won't go anywhere — the more often you'll catch these moments.
Here's the answer:
The problem archive, including:
- the question video,
- the answer video,
Don't do it, seriously.