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Today I gave a quiz on adding & subtracting negative numbers.

It went quite horribly – I obviously dropped the ball again somewhere.

The only time I ever had kids get it easily and quickly was when I likened positive numbers to people, and negative numbers to raptors1. The raptors eat a person, take a nap, and are out of the equation (ha ha). Works well for adding, but subtracting becomes a bit of an issue.

I think, though, that I can address that with camouflage and guns: camouflage is for subtracting humans, and nato rounds are for subtracting dinosaurs. We’d need an endless supply of extra matched dinosaur & people pairs for the odd times when you’ve got more camouflage than people, or more ammo than raptors. That, of course, would be completely available in the next valley over.

Then again, a lot of them got that basic concept, but had trouble generalizing it to larger numbers. I had them do observations and deductions, but during the practice time there was a lot of avoidance behavior. Obviously, I expected them to get too much at once. I keep forgetting that these are kids who don’t understand the applications of subtraction, much less division or multiplication.


1 My math coach told me today after school about a teacher at a local charter school who uses bloods & crips to teach this. That reassures me about the appropriateness of the dinosaur lesson.

{ 2 } Comments

  1. Benjamin Baxter | February 26, 2008 at 9:01 pm | Permalink

    I saw a teacher use two different gangs: Positiveños and Negativeños.

    He explained to the kids that the only difference was that Negativeños had to wear their sign all around the place, while Positiveños were confident enough without it.

    Say what you want. It worked quite well, and on multiple levels.

  2. Benjamin Baxter | February 26, 2008 at 9:02 pm | Permalink

    That funny symbol was supposed to be the funny looking n.