Random Cool Math Thing #3
Odd Perfect Squares
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Discrete Math
Clock Buddies — A Round Robin Tournament Activity
This is a great first day of class activity, which works well with math phobic students (I use it in a math for elementary teachers class). Students make a list 1:00, 2:00, etc. on a piece of paper — however many times I assign — and then they have to make an appointment with a different student in each slot. Students move around the room making appointments and learning each other’s names. If there are an odd number of students, I passively participate, accepting appointments whenever students come and ask me.
At some point a student or a few students will announce that they are done, and I tell them they aren’t done until everyone’s schedule is filled in. It’s an interesting question to figure out a good number of appointments to give them so that they will get stuck, but not overwhelmed; I usually go for a few more than half the number of students (12 for a class of 20). Read more >>
The Handshake Problem
The handshake problem is an old chestnut — if everyone in the room shook hands with everyone else, how many handshakes would there be? Then generalize. What I have to add to teaching the problem is a handout (doc version, pdf version) with different (fictional, but based on reality) students’ strategies for solving the problem. This handout is good for homework after students have worked on the problems themselves and listened to their classmates’ strategies. Read more >>
Pascal’s Triangle
I was pretty excited when I figured out how to use conditional formatting in Excel to make a Sierpinski triangle. I used very tiny cells, and then used conditional formatting to color in the cells corresponding to odd numbers in Pascal’s triangle. The video also introduces Pascal’s triangle and explores some number patterns. Spreadsheet used in the video (Excel 2003).
To do the conditional formatting in later versions of Excel, go to the Styles Group on the Home Tab. Choose Conditional Formatting, and then choose New Rule. Choose the last option, “Use a formula to determine which cells to format.” Then enter the formula as in the video.
