Guess the Age Activity for Introducing Absolute Value

Today I want to share a guess the age activity I used with my Algebra 1 students to introduce the concept of absolute value.

Monday was my students’ first experience with absolute value in Algebra 1.  A few students who took Algebra 1 last year already knew what absolute value was.  A few others wrongly described absolute value as meaning the opposite.  They thought it meant that you just changed the sign.

My students had been working really hard at multiplying binomials and factoring quadratics for the past two weeks.  Test scores were not exactly where I had wanted them, but at the same time I was proud of my students because I have seen them grown an incredible amount since meeting them in August.  In August, I would not have thought that my students would be factoring quadratics with a leading term greater than one.  But, we’ve gotten here.  We still need some more practice with factoring, but we will continue reviewing it and practicing it for the remainder of the semester.  And, it was a Monday.  So, I decided to kinda ease into our absolute value unit using the Estimating Age activity from Dan Meyer’s Algebra Curriculum (Week 3.)

I picked 15 of the celebrities from his file.  I used their birthdays to calculate their current age.  I typed up a half-sheet of paper for students to record their guesses.  It’s not perfect.  After using it once, I realized that I should have added a fourth column for students to record the difference between the actual age and their guess.  I don’t know if it would be of use to anyone, but I have uploaded my file below.

We went through each celebrity.  As a class, the students tried to guess who the celebrity was.  This led to some very enlightening conversations.  My students didn’t know who Natalie Portman was.  They didn’t recognize Penelope Cruz.  I thought for sure that the would recognize Julia Roberts.  No, they thought she was a character off of Sex and the City.  We had arguments over whether Tobey Maguire’s real name was Tobey Maguire or Peter Parker.  I was shocked to learn that one of my students thought Judi Dench was James Bond’s mother.  But, my other classes didn’t even know that she had played M in the James Bond movies.  Somehow, Ronald Reagan got brought up in my 8th grade Algebra class, and I learned that two of my 8th graders had no clue who Ronald Reagan was.  One student told me that they thought Morgan Freeman looked like the president of Africa.  But, others tried to convince me that Morgan Freeman looked the exact same as Samuel Jackson and Denzel Washington.  Another student was convinced that Will Smith was only 21.  

After my students had recorded their guesses for the age of each celebrity, I revealed the correct ages.  They wrote down in the margin how far off they were.  Then, we totaled this column.  The student with the lowest total won.  And, I didn’t realize how much of a controversy my award would cause.  Up for grabs was a much-coveted “Super Student Award.”  I picked these up at Dollar General during a 75% off school supplies clearance sale.  So, I picked up a few packs of awards.  At 25 cents for 24 awards, it was too good of a deal to pass up.  I thought my students might consider them childish, but I was wrong…  

One student was so mad when he didn’t win the award that he crumpled up his paper, tossed it across the room, and pouted for the rest of the class period.  He tried every way he could to get me to just write him a certificate, too.  I told him that I couldn’t do that; he would have to find a way to earn one.  Now, he asks every day if we are going to play the game again so he can win an award.

After playing the celebrity age guessing game, I started to transition to absolute value by asking my students to consider a scenario where a celebrity was actually 55.  If one person guessed 51 and another person guessed 59, who would win?  One of my classes was convinced that the person who guessed 51 would win because it just had to be like the Price is Right where you automatically lose if you guess too high of a number.  I assured them that we weren’t following the rules of the Price is Right.  Finally, we agreed that it was a tie because both guesses were the same distance from the true celebrity age.

In math, we aren’t worried about how close a number is to a celebrity’s age.  Instead, we want to know how close a number is to zero on the number line.  We filled out a Frayer Model on absolute value to glue in our interactive notebooks.

 We ended up Day 1 of the unit by practicing some order of operation problems that involved absolute value.  This was a great way to review absolute value without feeling like I was losing valuable class time.  A lot of my students left my class this day feeling more confident about math than I had seen them all semester. Our two previous units on exponent rules and polynomials have left some of my students with lower grades than last semester.  I hope my students realize that I am pushing them because I care for them.  We have made great strides this school year!

We followed this up with a graphing absolute value foldable.