Lesson objective: Use counting on to solve subtraction situations in the context of data.

This lesson provides an opportunity for students to apply their knowledge and understanding of operating with data to a real-life situation. Students are asked to solve how many flowers will be left in a garden, using counting on to subtract the tall flowers.

Key Concept students will use:

- We can use counting to subtract because figuring out how many to count on is the same as figuring out how many were added on.

Skills students will use:

- Solving subtraction situations.
- Relating subtraction to counting by using the counting on strategy.
- Writing number sentences to model addition and subtraction situations.
- Representing and organizing data in pictures and data tables.

Students engage in Mathematical Practice 4 (Model with mathematic) as they organize data in pictures and data tables and subtract the data, using the counting on strategy and modeling the situation with number sentences.

**Key vocabulary: **

- addition
- count on
- counting
- data
- data table
- difference
- number sentence
- organize
- part-part-whole diagram
- represent
- subtraction