This is a short reflection from a lesson focused on solidifying understanding of linear and absolute value equations with Grade 8 Algebra 1 Students.


I created a game, based on the Green Globs software.  I’ve never actually used the original materials, but it looked like it would be a highly motivating activity, and being on a tight school budget, I decided that since I wouldn’t be able to make the purchase, next best thing would be to use Geogebra to make my own materials.  I called my game “Bullseye.”  I bet that the original version is slicker and more complex than mine, but it worked pretty well for us.

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Here is what a “game board” looks like.   The basic idea of the game is that you need to write equations which, when graphed, hit the green dots.  Your team scores points based on how many green “orbs” your graph hits.

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I grouped students in pairs and gave them whiteboards.  I handed out the rules, and projected the game board.  Students had 2 minutes to decide on their best two equations.  At the two minute mark, we called “markers down,” and students held their equations in the air.  We entered them into Geogebra and calculated their scores for the round.  I also stole the scoring from the Green Globs people: for each equation, 2 points for the first orb, 4 for the second, 8 for the third, etc. doubling for each additional orb.  Asking them to work in pairs was key.  They were forced to talk and argue about the best two equations to choose.

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Students who spotted the absolute value equation in this one ran the table!

The “Expert” games included “Shot Absorbers.”  If your graph hits a shot absorber, you don’t score any points.  When these were on the board, I also allowed inequalities, but you might want to allow piecewise functions or Domain or Range restrictions if that’s where you’re at.

My 8th grade group this year is by far the most competitive group with whom I’ve worked.  They are just dialed-in when they are competing against each other (There is a total ruckus in the room when we play Grudgeball!).  I have to admit that I am not much of a gamer.  I don’t really play games, and I’m not a very competitive person.  But we need to adapt to the group that we have.  These kids are really pretty good sports.  They desperately want to win, but they are also good losers.  Even though Nathan Kraft has decided that it is potentially destructive to his classroom culture, it just works for my kids.  And as long as I have them playing in pairs or groups, at least there’s collaboration in addition to competition.

Here are about 12 game boards along with my instructions.  These could be very easily modified to work for quadratics or whatever functions you’re studying.  Let me know how it goes if you try this out, or if you have ideas for improving the game.

Bullseye Game Files and Instructions

UPDATE (2/7/2016): Of course several better versions of this activity surfaced quickly.

6 thoughts on “Bullseye

    1. Nat Post author

      YES!! Marbleslides has taken things to a new level. My students love it, and I can’t stop playing myself. I’ve used the linear activity with students so far, but I can’t wait to see what they do with the quadratic marbles.

      And you’re right about archiving the student work as well. Huge difference. Desmos rocks!

  1. Jessy

    This is great! I love it and I think it would work a bit better for my kids than some of those marbleslide things I’ve seen, which are addressing similar skills. I lost a week and a half this year while I was out on jury duty, but I think this activity would’ve fit in that time slot really nicely. Or maybe I could try it this year with quadratics, even. Thanks for sharing!

      1. Nat Post author

        Hi Jessy, and thanks for your comments. Interesting that you say that this game would work bearer than the marbleslides for your kids. None of these activities mean anything unless we can pair up the right one with the right group t the right time.

        1. Jessy

          Well my thought was that this would be good for my alg2 kids, but from what I’ve seen of the marbleslides, they have to set a domain restriction for each line? I could be misinterpreting that, but that class is def not ready for something like that (essentially piecewise functions). My precalc kids are, but they’re also past using lines. Would be fun to play marbleslides with like crazy trig functions or something?


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