How I Met Your Mother

[2018 Oct 30. After eleven years of learning, this lesson now seems obviously sexist and ableist and I’m not proud of any of that. I am leaving it up because I don’t see the value in sanitizing my learning process, gross stuff and all.]

Ha ha … oh man … *wipes tear* … this is awful. I can’t turn it off. The game’s just too easy right now. I mean, everyone’s serving me up these monster lesson plans. I’d have to walk around with my ears gummed up and my eyes blindfolded to experience even a little bit of a lesson planning block.

Exhibit A is, of course, The Red Dot (and how I taught it), a small blurb snatched out of an RSS feed and built into an hour of Algebra.

Exhibit B is CBS’ sitcom How I Met Your Mother which featured the following exchange last week. (Enjoy a YouTube upload of the scene or the following screenplay [which looks awesome outside the RSS feed].)

Luckless Ted (Josh Radnor) just met a girl online. Suit-sporting bachelor Barney (Neil Patrick Harris) interrogates:

  • So she's hot?
  • TED
  • Oh she's gorgeous.
  • Then ... she's crazy.
  • TED
  • No she's not.
  • There's no way she's above the line on the hot/crazy scale.
  • TED
  • She's not even on the hot/crazy scale. She's just hot.

Robin (Cobie Smulders) asks for an explanation of the hot/crazy scale, a scale which fits our current lesson plan like that embarrassingly tight t-shirt you’ve gotta suck in your gut to wear.

See, as Barney explains, being crazy is fine so long as you match your neuroses with good looks in a one-to-one correspondence (or better). Which makes sense.

In a fantastic hey-mister-scientist moment, Barney terms that line the Vickie Mendoza Diagonal, which, I mean, holy cow, I don’t care who you are, there’s no way to mess that one up.

But again, I didn’t care about the base hit. I wanted the home run, lights exploding as I rounded the bases, etc.

So I fabricated ten ex-girlfriends and ranked them on a ten-point scale for looks and sanity.

I asked the students to graph ’em and tell me which ones fell above the Vickie Mendoza Diagonal.Another question asked, totally straight-faced: “Is Mr. Meyer monogamous?”

I also put a length to each relationship and a start date, including two more graphs, which yielded interesting conclusions about a) the length of the relationships as my girlfriends got crazier,

and b) the hotness of the girls I dated as I got older.

It was fun. So fun.

I showed ’em individual dot plots of length and crazy and pointed out how they didn’t reveal anything

Then I put ’em all on the same scatter plot and the thought farthest from their minds at that moment was, when could we ever use this in real life?

Oh man … I swear, if I wasn’t a teacher, I’d have that screenplay banked by now plus four more on top of it. Such is the creativity this job demands.


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  4. Quicktime Movie
  5. Handout
I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. He / him. More here.


  1. Just goes to show you – I enjoyed the entire episode without it ever crossing my mind about the math in it! Thanks for your wonderful perspective!

  2. Excellent! Your further analysis of Barney’s Crazy vs. Hot scale is truly awesome. Truly you have a dizzying intellect as seen by the graphs… makes me want to plot all my past relationships out to see how the graph would look. Either way…thanks for the laugh.

  3. Simon Oldaker

    March 25, 2009 - 7:54 am -

    If you don’t mind goofy conceptual digressions, then you should check out ‘Le grand content’: a video made from Jessica Hagy’s graphs. I can’t really explain which point in the curriculum this is going to come under, but I’m going to show it to my class anyway…