Lesson objective: Organize additional data into a data set by using counting on to add.

Students bring prior knowledge of counting by ones and adding from K.CC.B.5 and K.OA.A.2. This prior knowledge is extended to relating counting to addition as students are counting on from a given number as a strategy for addition. A conceptual challenge students may encounter is believing that they must count all of the data points one by one rather than counting on from a starting amount to find the total.

The concept is developed through work with a data set, which allows students to count on and model the data being added to the original set in a picture or the beginnings of a picture graph.

This work helps students deepen their understanding of operations because when we are adding to a number, it is the same as counting on from the number where we started.

Students engage in Mathematical Practice 4 (Model with mathematics) as they organize and represent data in different visual formats. They will create a picture of their data organized to model the planting of seeds in a garden. Students will also engage in Mathematical Practice 1 (Make sense of problems and persevere in solving them) as they use the context of data to reason through rich situations involving addition.

**Key Vocabulary:**

- add
- counting on
- data
- data point
- organize
- picture graph
- represent
- table
- tally mark

**Special Materials:**

- graph paper (optional)