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 Goods**

The problem archive, including:

- the question video,
- the answer video,

Don’t do it, seriously.

## 8 Comments

## Karim

January 26, 2011 - 10:01 am -Great find! Actually seems like fair game to me, and certainly tamer than “half plus seven” (which makes for a great Algebra lesson). Why are you reluctant? I’ll take it if you don’t want it.

Here’s one that definitely shouldn’t be taught, though. Or maybe it should. Cost per ounce? Rations and proportions all over it. Great math. Seems like a waste not to.

## Chris Sears

January 26, 2011 - 10:35 am -So, I’m not the only one who remembers “half your age plus seven.” I thought it was funny that Tom could do it in his head to one decimal place.

On the theme of look for math where you see it, I just used one of Jared Loughner’s YouTube videos in my Contemporary College Math class. I was talking about how his video presents the Law of Detachment perfectly, even though his premises are incomprehensible.

I’ve also used multiple videos from Big Bang Theory. The math always works out on that show.

## Andrei

January 26, 2011 - 10:53 am -One thing I was surprised to find when I went into the ‘real world’ is that ratios like ‘cost per ounce’ are actually pretty tame. Real situations often call for the fuel per passenger mile (on a ‘plane), or the employee hours worked per guest per day (at a hotel).

## James D

January 26, 2011 - 2:35 pm -It seems like it could be entertaining with mature enough kids. Certainly agree with you Andrei, those real world ratios are the best for getting kids going on something.

## Aaron F.

January 29, 2011 - 11:03 pm -The thing that always got me about the “half your age plus seven” rule is that if you take it seriously, it actually makes an interesting prediction! Specifically, it tells you that people younger than a certain age shouldn’t be able to date *anyone* without being creepy… and that age turns out to be fourteen, which seems pretty accurate!

## Dan Meyer

January 29, 2011 - 11:35 pm -I did this in Doha, Qatar, yesterday with some teachers and they told me we’d have to adjust the formula to “one-fifth plus seven.” Ew.

## Brandon

January 31, 2011 - 11:14 am -Another video all about scale factor, ratios/proportions, etc. — http://vimeo.com/bradgoodspeed/scale