Thursday, February 5, 2015

Absolute Value Equation Game

When I teach my students about solving Absolute Value Equations I emphasize both the graphical and algebraic representations.

When students are confronted with an equation such as |x-4|=7 I require them to tell me:

  • the meaning, "The distance between x and 4 is 7."
  • to create the graph

  • and to solve algebraically

Topics Covered:

Solving Simple Absolute Value Equations

Game Name:

Hmm.  I'll get back to you on this one.

Game Objective:

Be the team that collects the most points.


Large Number Line from -20 to 20 (draw one on the class board).

Deck of playing cards, jokers removed.

Color paper cut into gem shapes (Blue, Green, Red, and Yellow) about 2 inches in diameter, at least 20 of each color.  If you have time to laminate that would be helpful.  

Small cheap magnets or tape.  Attach a small magnet to each gem or just a piece of tape to the gems so that they can stick to your board.  

Pawns (8-12) two for each team with magnets attached if you have a magnetic white board.  My pawns are strips of color paper where I printed "Team 1" and laminated.

Set Up:

Divide the class into 3-6 teams.  This is a turn based game, therefore you don't want too many teams. 

Draw a large number line on the board so that all students can see it.  Number it from -20 to 20.

Under each number place a gem.  There will be many left over, but they are used as the game progresses.

Write each team name on the board.  Leave enough room underneath for them to place all the gems they collect.  

Deal 5 cards to each team.  

Game Play:

On a team's turn, they use two cards to create an Absolute Value Equation.  Ace through 10 represent the numbers 1-10, and a Jack represents 0.  I'll get to the Queen and King in a moment.  

Suppose a team decides to play the number 5 and 2.  They may create the equations |x-5|=2 OR |x+5|=2 OR |x-2|=5 OR |x+2|=5.  Have one of the team members come up to the board and write their equation on the board, hand in their two cards, and move their pawns to the corresponding values of x.  Remember to give the team 2 new cards at the end of the turn.

Once the team moves their pawns to the correct place on the number line, they take the gem from each number, if there are any, and place them under their team name on the board.

In the beginning of the game, I try to emphasize where the 'center' is (in the above example the center is -5) and the distance from the center (in this case the distance is 2).

If a team is able to create an equation with only one answer.  They move both of the pawns to that location and can take one gem.

If a team lands on the same number as another team, they must steal one gem from them (any color) and take the gem they land on.  Again, if they move both their pawns to one location they must steal 2 gems from that player.

One more "if".  If a team moves to a location that has multiple pawns on it, they must steal one gem from each of those teams.

After a team is finished, place new gems on the number line to replace the ones that were taken.  At some point in the game you may run out of gems.  That's okay, the teams will then have to focus on stealing gems.

What's with the Gems?

Initially the gems are worth 0 points, but the value may increase or decrease depending on what the queen and king decide.

A team may decide to play a queen or a king card on their turn rather than moving their pawns.  A queen card will decrease the value of a gem.  It is possible that gems are worth negative points.  A king card will increase the value of a gem.

Write/post this somewhere because the students will forget.

Suppose a team plays a king and a 7.  They may increase the value of any color gem by 7 points.

Also, if a team plays a queen and a 9, they may decrease the value of any color gem by 9 points.

If a team has all kings and queens in the hand, trade out those 5 cards with 5 new ones.

Winning the Game:

I play this game for about 35-40 minutes.  The team with the most points at that time is the winner.

For one of my classes the gems ended with the following values:

Team 1 has a total of 29 points...

Team 2 had a total of -97 points...

Team 3 had a total of -19 points...

Team 4 had a total of -20 points...


Another kingdom story.  I couldn't resist once I decided to use playing cards.  I mean a king and queen, come on!  Anyway, each team is a peasant in the kingdom trying to impress the king and the queen.  They mine anywhere and everywhere to find precious gems to win over the royalty.  Problem is, the king and queen keep changing their minds on the value of the gems.  Be the team to impress the royal couple and earn your bragging rights.

How Did it Go?

I played this game with two of my classes and it went well.  Initially, the students weren't sure why they were collecting gems (even though I told them) and just went for it.  But this went well to help them understand how to solve the equations.  Once the teams started to change the value of the gems that's when the magic started to take place.  The students were trying to create equations so that they would 'land' on certain colors or other teams.  They were strategizing as to when to play a King or a Queen.  EVERYONE was engaged and surprised when I told them the bell was about the ring.


  1. Like this! I wonder if you could play it simply as a three or four in a row game. You play |x+-2|=5 and put X on 3 & -7, I play |x+3|=4 and mark O on 1 and -7 oops you've got that. Red cards negative. Players keep a hand of four cards...

    OK, it's a whole 'nother game. I like your mechanic, too, it means.

    1. I like your idea and the simplicity behind it. I wonder how that would play out since there are more ways to land on 1 than 20.
      I would like to play test this if there's time.

  2. We played this game in class today! Loved it! Thanks for sharing!

    1. Great! I'm so glad other teachers are using my games.

  3. Yes, an awesome game! I had too many gems though, so the game didn't get to a blank board early enough. Wondering if it would be better with no extra gems, just the original 41.

    1. It's probably is not necessary to have extra gems. That would force the players to target each other.

  4. I tried this game in my classroom (8th grade math 1) last week. It worked so so well! Thank you so much for sharing.

    1. Yeah! I'm happy to hear that others are using my games.