Day 151: Dice

Geometry is shifting into a little bit of stats for geometric probability. I started students off by playing three different dice games:

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For each game, I had the winner raise their hand and say if they were Player A or B. We discussed why or why not the game was fair. The last thing students looked at was if there was a way to fix the game and make it fair.

Day 139: Factor Dice

Today is Friday; one strike.

I also introduced factoring trinomials; two strikes.

It ended up being one of the best days of the year.

I was frantically digging around the MTBoS looking for activities to introduce factoring. I came across a whole lot of crazy techniques; X method, diamond method, bottoms up…. Honestly, none of them made sense.

Then I came across this gem over at Dan Meyer’s Blog.

I pulled out a whole lot of dice from the department closet and after our opener I rolled a couple in front of the class. I told ’em that my dice added to 9, paused for about 15 seconds, them told ’em that the two multiplied to 18.

No sweat.

We did a couple more, then I broke the class into groups of two. Each group had two dice; a red and green and a folder to shield their dice. One person rolled the dice, calculated their sum and product then the other guessed.

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They messed around with those for a while, this got old for some of the groups, so I gave ’em two more dice.

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They added the red dice to create a number and did the same with the green dice. Then one student calculated the sum and product while the other student guessed the value of the dice.

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For some groups, this wasn’t even enough. So… I kept increasing the number of dice.

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Somewhere in between one, two, and three pairs of dice I upped the difficulty even more:

Green = Positive

Red = Negative

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So now the sum is -2, and the product is -80.

This activity lasted about 15 minutes. I had 100% engagement across the board in 4 periods of algebra. No joke.

Students went back to their seats and I put this up on the board.

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Last year I had students expand out binomial products till they picked up on the pattern. This year they looked at why A and C wouldn’t work here. We talked about how FOIL works, which I have actually been referring to as F (O+I) L this year.

Then things clicked.

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Students understood where all that work with the dice came into play.

After a couple more multiple choice sort of problems, they were on their own.

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I am fully aware that the dice activity only serves as a stepping stone in developing factoring skills. However, I threw up a couple of trinomials with a = 2 and students took them down. They understand that factoring these things is a guess and check process, and with more practice things will get easier.

Monday will be the true test to see how well they absorbed everything after a weekend passes.