Lesson objective: Collect, organize, and compare data using the relationship between addition and subtraction.

This lesson provides an opportunity for students to apply their knowledge and understanding of comparing data from a graph to a real-life situation. Students are asked to organize the data taken from a class survey into a graph and compare the categories.

Key Concept students will use:

- We can organize, represent and interpret data (up to three categories) and make comparative statements about the values in the categories using our knowledge of numbers.

Skills students will use:

- Apply properties of operations as strategies to add and subtract (Grade 1, Unit 6)
- Understand subtraction as an unknown-addend problem (Grade 1, Unit 6)
- Organize, represent, and interpret data up to 3 categories and ask and answer “total” questions (Grade 1, Unit 2)

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:**

- Monster Posters
- Graphing sheet
- white boards/markers or paper/pencil
- number lines to 20