In Topic A, student work revolves around categorical data, which is produced by sorting objects or information into categories. For example, students learn about categories of animal classes and habitats and then record those data in a table. Students also learn to use picture graphs and bar graphs to organize and represent the data in as many as four categories (2.MD.10). They learn that this organizing of information makes it easier to compare data and can help them solve problems. In Lesson 1, working within a science context, students categorize animals into classes (mammals, birds, fish, and reptiles), organize them in the form of a table, and then use the category counts to solve simple put-together, take-apart, and compare word problems (2.MD.10). Students then repeat the process, sorting animals by habitat to create a second data set. They record category counts in the tables with both numerals and tally marks (see image below). Animal Habitats Arctic Ocean Woodland Animal Classification Birds Fish Mammals Reptiles 6 5 11 3 In Lesson 2, students learn to draw and label a picture graph using the data from Lesson 1. Grid paper provides support as students construct these graphs. They learn that a graph can be oriented horizontally or vertically, and that each picture represents one object. Students ask and answer questions based on the information displayed in the graphs. Following the same procedure and using the same data as in Lesson 2, students learn to draw and label a bar graph in Lesson 3. They learn that one axis names the category while the other shows a single-unit count scale. As students ask and answer questions based on the data in the graphs, they relate the count scale to finding sums and differences on a number line diagram. In Lesson 4, students continue working with bar graphs to represent new data sets and solve simple word problems. Topic A culminates in Lesson 5, as students display money data in a bar graph and use this data to solve word problems. This leads into problem solving with coins in Topic B.