## Sunday, November 6, 2011

### Sum of Three

I got this activity from my brother-in-law and really like it.  It is called "Sum of Three".   In essence you have students in groups of three each doing a different problem.  Then you have them add the answers together to be the sum of the three answers.  They will bring this number up to you and ask if this is correct.  If they are correct, then they get to move on to the next problem set.  If they are incorrect, then they must decide how to go about getting the correct answer.  This is the best part of the activity.  When the students get the problem wrong, they automatically think it is somebody elses mistake.  They then will systematically go through the process of how to do the problem with everyone.  It is a great group activity.  Here are my directions.  I have given a couple examples as well.
1.  Get your class into groups of three.   I always do this on a random basis.  Let's say you had 26 people in your class.  Take 26 kids divided by 3 and you get 8 full groups of three.  Count students one, two, three, and so on till eight, then start back at one, two, three and keep doing this until you run out of people.  In this case, you will have 6 groups that have 3 in it and 2 groups that have 4 in it.  Now the ones get together and the twos get together and so on.
2.  Hand out a problem set A in paper form to each group.   This will have three problems in it.  A1, A2, and A3.  Each student will work on a different problem.  The group will then add the sum of all three answers.
3.  When a group thinks it has a sum, they bring up THEIR PAPER to show you their answer.  Don't have the students SAY the sum.  This might give it away for the other students.  If they are correct, give them the problem set B in paper form.  If they are incorrect, then they must go back and find out where they made a mistake.
4.  I have my students do all their work on a separate piece of paper to be turned in.  This creates a little accountability as well as a place for them to work.
5.  You will have to decide how many sets of problems you will want.  I typically have 3 to 4 sets.  I have the last set as extra difficult.

Here are a couple of examples of the "Sum of Three" activity.

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 This is a problem set for multiplying fractions in Intro to Algebra
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 This is the answer sheet that I use when the students come up to give me their SUM.
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 This is an Algebra "Sum of Three" problem set.  I have the students add the y-intercepts of the line. PDF of the FRACTIONS "SUM OF THREE" ACTIVITY PDF of the EQUATION OF A LINE "SUM OF THREE" ACTIVITY

Lisa Parisi said...

I teach elementary school and often do something similar but easier to manage. I give students a problem and tell them that they can't go on to problem 2 until everyone at their table has the same answer. They often assume they are correct and the others are wrong. They have to show each other the errors. Works well for collaboration and kids love it.

Michelle Burton said...

What a great idea - thanks for sharing! I do quite a bit of partner work, but I especially like this for the group accountability ....without having to say who is right or wrong. Having students help each other is such a powerful activity!

instillnessthedancing said...

Returning to the classroom after several years as a principal ... so I'm looking to blogging colleagues for ideas. I love the "Sum of Three" idea and will put it to good use!

Roberta Brant said...

Love this idea. I play a similar game where everyone in the group has a paper and they all work on the same problem. One person in a group is the runner. They bring the paper to me and I check to see everyone has work and it is correct. I love this idea better.