Add 'Em Up: A New Strategy for Me

As is often the case at this time of year, the winter weather is breaking up my lessons. I introduced stoichiometry, or what I call reaction math, on December 13 but some snow days and semester exams put it on the shelf almost immediately. Now that we are back to school, I needed a way to help students review what they began almost one month ago. 

I am often inspired by the tweets and blogging of Sarah Carter. I haven't met Sarah, but I know she teaches math and chemistry in Oklahoma. I read her detailed blog posts where she generously shares many great ideas with great interest. Sarah has written about a favorite strategy called Add 'Em Up and her posts were the inspiration for this lesson.

In Add 'Em Up, a sheet is created with four math problems. When the answers are added, they should equal a sum that is provided. If the answers do not equal the sum, students know they need to look for, and correct, their errors. With my teaching partner, I created an Add 'Em Up activity for stoichiometry with a few revisions. We created four sheets of four different math problems. Today we instructed the students to solve a problem on the sheet they had and then pass the sheet to the student on their left at their table and solve another until all four were solved. 

Once the problems were all solved, students added the digit in the ones column of each answer to get their sum. We didn't tell the students at first that these digits would be 2, 0, 1, and 8 (because welcome back to school for 2018!), so the sum would be 11, but we eventually revealed the sum and the digits to streamline the process of finding the mistakes.

Part of "welcome back to school for 2018" in my classroom is getting new seats and new groups. Today was the first day in new groups for my students, so I wanted to do an activity to help the students get to know each other and build some teamwork. This was perfect for that. Because the papers were passed from student to student, every student worked on every paper. When they got back to the original participant, each student had to evaluate each other's work and investigate errors. While they worked, they were incredibly collaborative despite the fact that they all had different problems. There were excellent conversations all day long in these new groups. They really worked together nicely to get to the correct sum on each paper. Things I heard students say to each other included:

• Does that make sense?
• I'm not sure about the coefficients. What do you think?
• Can I use a whiteboard?
• Someone please help me.
• Is this the way you solved number 2?
• Should we all just check one problem?
• Can I use this problem as a model for this one?
• I know Ms Roediger likes dimensional analysis but it makes more sense to me with ratios.
• Oh, cool (when he saw the 2, 0, 1, 8).

I loved the strategy and am looking forward to trying it again sometime. If you'd like to take a look at the file, you can see it here. Make yourself a copy if you'd like to use or modify it. And check out Sarah's blog. It's amazing!