Trig War

This is going to be a quick post.

Kate Nowak played “log war” with her classes. I stole it and LOVED it. Her post is here. It really gets them thinking in the best kind of way. Last year I wanted to do “inverse trig war” with my precalculus class because Jonathan C. had the idea. His post is here. I didn’t end up having time so I couldn’t play it with my kids, sadly.

This year, I am teaching precalculus, and I’m having kids figure out trig on the unit circle (in both radians and degrees). So what do I make? The obvious: “trig war.”

The way it works…

I have a bunch of cards with trig expressions (just sine, cosine, and tangent for now) and special values on the unit circle — in both radians and degrees.


You can see all the cards below, and can download the document here (doc).

They played it like a regular game of war:

I let kids use their unit circle for the first 7 minutes, and then they had to put it away for the next 10 minutes.


And that was it!



  1. I saw that you did this on Twitter and was going to email you for the document. Sadly, it’s too late for me this year, but I hope to use this next year. THANK YOU!

    On Fri, Nov 22, 2013 at 10:35 AM, Continuous Everywhere but Differentiab

    1. Hahaha, I debated that. I don’t know why I chose to make it a losing card. Why would you make it a winning card? I was thinking because it was like INFINITY it would win, but depending on how you approached it, it would be negative infinity. So I just said, eh, lose.

  2. This is super cool.

    I can imagine students bickering about who wins, proving who is correct, kids using rough estimation to see who’s right, appealing to the definition of the unit circle to get rough estimates of sine/ cosine. …

    I also imagine a twist: for each round, have a small deck of different outcomes: for example, winner earns 2 points, winner earns 4 points, loser wins 2 points, loser wins 1 point, etc… . Lat that down first, THEN If each kid has a deck of say 12 trig values , give them 5 seconds to pick a card from their deck and play it… ties carry over to next card.

    Yay – cool!

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