Sunday, September 23, 2007

Using Tally Marks to Solve Problems

In second grade, we really focus on increasing number sense with our students. One of the ways that we do this is to encourage student to have a bank of strategies to help them solve problems. I am going to go through each strategy as we go over them in class. This first strategy tally marks in groups of 5 was introduced in first grade. We review it at the beginning of second grade for those students who did learn it in first and introduce it to those students who have not learned it yet.
Sample problem: 12 + 10 = ___

1. Make a representation of the problem using tally marks in groups of 5. It is helpful to some students to circle the two groups to make sure that they did not leave anything out.

2. Count all of the groups of 5. Students are always encouraged in class to show all work.

3. Count any single tally marks that are left after the groups of 5 are counted. The hardest part for students in this strategy is to go from counting in groups of 5 to counting singles. (For example, instead of counting 5, 10, 15, 20, 21, 22 students may try to count the single tally marks as groups of 5 like 5, 10, 15, 20, 25, 30.)

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