Addition Strategies Seminar

Guess My Strategy. Write the problem 4 + 3 on a display. Ask the class to watch carefully but not to say anything as you solve the problem. Remind students that there are several different strategies that someone can use to solve the problem. Their job is not to solve the problem, but instead to watch you and guess your strategy so they can describe it.

Without explaining what you are demonstrating, hold up one hand with 4 fingers extended, the other with 3 fingers. Point to the hand with 4 fingers, and write "4."

Then count on, touching one finger at a time on the second hand, and write "5, 6, 7." Write "7" as your answer to the problem. Ask student to identify and explain your addition strategy. If they describe it but don't name it, call it the "counting on" strategy. Write the steps on the display. See Figure 7.

Then do a silent demonstration of the using doubles strategy. Write the same problem, 4 + 3, on the board. Hold up a train of 4 red cubes. Add a train of 4 yellow cubes. Write, "4 + 4 = 8." Take away one yellow cube and write, "4 + 3 = 7."

Ask volunteers to explain your strategy. Write the steps on the display and ask students to justify them, as shown in Figure 8. Accept descriptions that reasonably fit the steps you modeled while solving the problem. Encourage students to break it down into both mental and action steps.

Assign the How Did They Do It pages in the Student Activity Book to assess students' understanding of addition strategies. Have connecting cubes readily available.