In this lesson, students share their preferred addition strategies, explaining the reason they choose to use a particular strategy for a particular set of addends. For instance, when adding 39 + 43, one student may prefer to use the "make ten" strategy, decomposing 43 into 1 and 42, because adding 40 + 42 is an easy problem for her. Another student may prefer vertically aligning the numbers to ensure that he is adding ones with ones and then tens with tens. Students discuss questions such as, "In which number bonds do you see an easier problem to solve? Is there another way to solve this problem? How are [the selected student's] methods different from or the same as your partner's? What is a compliment you would like to give [your partner]?"