Example:

Three best freinds, Shannon, Carla and Neka, were comparing their CD collections, to try and figure out what play list to put together for the upcoming school dance. Over 500 students were expecting to come and the party would be lasting 3 hours. The IPod they had could hold up to 15,000 songs !
Looking at their CDs they first counted them all and found that in total they had 100 CDs, but they all did not have the same amount of CDs. Making piles of the CDs they found that Shanon's pile was 4 CDs higher than Carla's, and Neka's was 2 CDs higher than Shanon's. All toghether the CDs weighed 2200 grams. They would like to know how many CDs each of friends owns.
With all the good music and everything else that goes into the party they just know that the dance will be a success.


Just the Facts:
Shanon had 4 more CDs than Carla

Neka had 2 more CDs than Shanon

In total they had 100 CDs

Problem Statement: How many CD's does each person have?

Procedure: I figured out who has the most, middle, and least number of CD's by the clues. Neka has the most, then Shannon, then Carla. I figured out that Shannon, Carla, and Neka were all going to have about 30ish CD's because 100 divided by 3 is about 33. Then I used the guess and check method. I started with Carla. I assumed that he had 32 CD's. That means that Shannon has 36 and Neka has 38. Since 32+36+38=106, I knew that I had to get rid of 6 CD's. In order to keep the differences the same, and follow the clues, I took 2 away from each person.

Now I have that Carla has 30, Shannon has 34, and Neka has 36. Since 30+34+36=100 then I know I have the right answer.

Conclusion: Carla has 30 CD's, Shannon has 34, and Neka has 36. The problem makes sense because I though they would all have about 30 CD's and they do. I think that the guess and check method was a good method to use. I liked how I subtracted two from each person when I had 6 CD's too much becuase taking two each away made the six.


Extension: We can add a 4th friend to the CD collection and say that there are 150 CDs in total and that the new friend has twice as many CDs as Shannon and Neka combined.