Topic A begins with a
lesson in which students generate categorical data, organize it, and then represent it in a variety of forms.
Drawing on Grade 2 knowledge, students might initially use tally marks, tables, or graphs with one-to-one
correspondence. By the end of the lesson, they show data in tape diagrams where units are equal groups
with a value greater than 1. In the next two lessons, students rotate the tape diagrams vertically so that the
tapes become the units or bars of scaled graphs (3.MD.3). Students understand picture and bar graphs as
vertical representations of tape diagrams and apply well-practiced skip-counting and multiplication strategies
to analyze them. In Lesson 4, students synthesize and apply learning from Topic A to solve one- and two-step
problems. Through problem solving, opportunities naturally surface for students to make observations,
analyze, and answer questions such as, "How many more?" or "How many less?" (3.MD.3).