Random Numbers to Spark Student Thinking

In my last post, I mentioned attending a session presented by Jennifer N. Morris on making math meaningful. (She is presenting two times at #NCTMRegionals Nashville – Session #244 for 9-12 and Session #275 for 3-5, which is the Origami/Fraction/Random Number session – BE SURE TO CHECK HER OUT – She is AWESOME!). One of the activities in her session incorporated the fx-55plus calculator and using the random number generator to spark engagement, problem-solving, numerical thinking and communication with students. Simply by hitting the random # key, which creates infinite random fractions (many complex!) and have students (participants) determine if that random number was acceptable if it represented the part of a cookie they would receive led to amazing thinking. What is acceptable? What are target fractions? How are students making their estimates and decisions? How do you know yours is bigger or smaller than the person next to you? Participants were asked to line themselves up in order, least to greatest, using their random fraction, which sparked great discussion and comparison. They checked their lineup by converting the fraction very quickly to a decimal, so equivalency and number sense.

During the discussion about all the different concepts students could be focusing on (number sense, fractions, estimation, equivalence, conjectures, probability, etc.) from this simple random number generation, teachers in the session offered several suggestions for using the random number generator on the calculator.  Here are just a few:

  1. Use Random Integer to simulate the roll of a die for data collection (you could use two calculators to simulate two die).
  2. Assign every student a number, and then use Random Int constrained to the numbers in the class (i.e. 1-20).  Use Random Int to pick a number, and that student is the one called on
  3. In Collaborative Groups, assign each group member a number and use random number generator to determine who in group shares, or leads

Jennifer used the fx-55Plus because she loved how easy it was to generate the random numbers. Someone in the group asked about the scientific calculator and graphing calculators, and did they also have the random number generator. The answer was yes, but it was a bit more involved. So – realizing that using random numbers is useful no matter the grade you teach, I thought I would show a quick video on how to generate random numbers using the Casio calculators. The great thing about Casio is that calculators with the same face-plate layout have the same steps. I’ve listed below the calculators I am demonstrating and then some other calculators that would have similar steps to generate random numbers:

  • Fx-55Plus
  • Fx-350EsPlus, fx – 300ESPlus, FX115-ESPlus, fx-991EX
  •  fx-9860GII, fx-9750GII, fx-CG10Prizm

Go be random!!

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