absolute value

Date December 2005
Class 8th grade
Teacher Joyce Cook

I used the age problem to help students understand absolute value.  They enjoyed guessing the ages and then figuring how far off they were.  When they looked at the results, they could see that their difference was always a positive number—it didn’t matter whether they guessed too high or too low.  I then talked about the concept of absolute value and how it was like that. I thought the lesson went very well.  I don’t think I would change anything.

Date Nov. 5, 2005
Class Pre-Algebra
Teacher Cassandra Joseph

My classes were just introduced to absolute value last week, so to drive home the point that they (absolute values) are always positive, I did the Ages activity with them on Friday. 

I gave them a few minutes to estimate how old people on the list were, then I went through and gave them the year they were born and their correct age.  After that they had to calculate the difference between their guess and the person's actual age.  I asked them since I didn't care whether they had them older or younger what were we getting...They all got that we were getting the absolute value of the difference.

The kids had fun trying to guess the people they didn't know, and Disney World messed everyone up (can anyone explain why if they were opened in 1962, they are having their 50th birthday??).

I will definitely us this one again, but I may change some of the people.