Lesson objective: Organize, represent, and interpret data and compare the values in three categories.

Students bring prior knowledge of understanding subtraction as an unknown-addend problem from 1.OA.4. This prior knowledge is extended to comparison situations as students compare the data on a picture graph. A conceptual challenge students may encounter is understanding the comparison language.

The concept is developed through work with number lines, which allow students a visual model of the distance between the numbers they are comparing.

This work helps students deepen their understanding of numbers and operations. By determining the distance between two numbers, students understand how these numbers are related.

Students engage in Mathematical Practice 1 (Make sense of problems and persevere in solving them) as they notice that they can use the properties of operations and the relationship between addition and subtraction to solve comparison situations from data using the number line.

**Key vocabulary:**

- addend
- addition
- category
- collect
- compare
- data
- graph
- greater than
- interpret
- key
- less
- less than
- missing addend
- more
- organize
- picture graph
- represent
- subtraction
- tally mark
- unknown number

**Special materials needed:**

- white boards/markers or paper/pencil
- number lines to 20