Teacher presentation materials. Unit: 2.1 Adding, Subtracting, and Working with Data (Grade 2). 2.1 Adding, Subtracting, and Working with Data Unit Goals Students represent and solve story problems within 20 through the context of picture and bar graphs that represent categorical data. Students build toward fluency with addition and subtraction. Section A Goals Build toward fluency with adding within 100. Build toward fluency with subtracting within 20. Section B Goals Interpret picture and bar graphs. Represent data using picture and bar graphs. Solve one- and two-step problems using addition and subtraction within 20. Section C Goals Make sense of and interpret tape diagrams. Represent