In this lesson, students represent and solve Put Together/Take Apart, Total Unknown story problems. These problems have no explicit action, and students must determine that this type of story problem is about two addends and their total. Rather than representing actions, students begin to understand that they are representing a part-part-whole relationship.

The opening activities use a numberless word problem and the Three Reads routine to focus students’ attention on thinking about what needs to be counted and the relationship between the quantities. The second activity introduces the idea that the two addends can be written in either order and that both orders represent the relationships in the story. Students’ representations and solution strategies also reveal that they can add from the first addend or from the greater addend. Students will continue to explore this idea throughout the unit.

Identify ways the math community you are working to foster is going well. What aspects would you like to work on? What actions can you take to improve those areas?