From Fist Bumps to Formulas for Series

This is my first time teaching series.  Thank goodness I have the amazing Sam Shah to give me his great ideas!

The fist bump problem is essentially the same as the famous “handshake problem“, but way better because of FIST BUMPS!  You should read all about it on Sam’s blog because he not only describes it really well, he has a hilarious fist bump video short that my kids loved.  Sam finds the best YouTube videos.

So after having them talk about how many fist bumps we would have in our class, I asked them how they could all fist bump each other most efficiently, then I actually had them act it out.  Even in my last class of the day students were eager to get up and try out their fist bump efficiency strategy.  I don’t know if you teach high school students but this is a BIG win.  They never want to get up. like EVER.  And, the last class even told me, “I heard we move in class today.  Please don’t make us move.”  Yet, they jumped up.  I think it was because I had them come up with their own theories to test out instead of me telling them how to do it.

Sam timed his students fist bumps but I did not because I did this on a short day (55 minutes) instead of a block day.  Ok, I did decide to time my last block because hey, it WAS the last class of the day and I was dying to time it.  Plus, it was THE LAST CLASS OF THE DAY and even after begging me not to make them move when they first got to class, they happily jumped up to fist bump after working on the problem.

If you want your students to understand what is happening and even develop the partial sums for arithmetic question, you MUST give them time after the fist bumps to work.  I took their suggestions about how to sum up a ton of numbers and then introduced them this method.  I did not show them the video.

I tend to rush them, but it was Monday, so I let them work longer than usual.  Wow, was I impressed.  Almost all students were able to write a partial formula to describe what was happening.  Several students actually developed the entire formula.  I did not push them to use variables until their equation was very close, but many students jumped to variables right away.

I should have taken more pictures, but I was having way too much fun!  I did get one picture of a white board from the last block.  They figured out the formula and stayed after class to try to finish it.  What a great day!


I have been giving hi-fives a ton this year so some students actually hi-fived me instead of fist bumping me when I went through the line.  I love that.

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