Friday, October 23, 2015

Age and Absolute Value

I read about an activity this summer to introduce absolute value to my students. It came from a Dan Meyer blog post

I introduced this as a game. I posted pictures of celebrities and students guessed their age. Then I posted the real age of the person and student recorded that next to their guess.

We had to decide as a class who the winner was. I asked the students how we could decide. Depending on what students came up with at first, I would prompt them with questions.

Eventually, I wanted them to say that they would calculate the difference by subtracting the guess from the actual age. If their guess was under, they would have a negative score. If they guess over they would have a positive score.

Now, we had to decide who was closer. If we added all the scores, then the negatives and positives together would make the score seem less than it actually was.

So now, I needed the students to decide to just calculate how far away from the real age they were. If they guessed the right age, their score would be zero. If they guessed one year over or under, their score would be one. Then I would connect this to absolute value and the number line. Again, depending on the class and what the students said, I had to guide them through questioning.

Here is the Google presentation I use. You can see it and Make a Copy if you want to make any changes and have one for yourself. Go to File, then Make a Copy and it will be saved to your Google Drive.

(If you aren't using Google Drive, you should be. I hated it at first, but I love it now).

I did have a picture and my age in the original one. If you are comfortable sharing your age, you could add your own.