Lesson objective: Understands that numbers exist in a sequence that does not change, and they can be counted.

Students bring varied prior knowledge of numbers from their experiences before kindergarten. This prior knowledge is extended to rote counting up to 20 as students practice counting. A conceptual challenge students may encounter is understanding that the numbers must be said in the same order every time.

The concept is developed through work with hands holding up a given number of fingers, which helps create a visual image and context for rote counting.

This work helps students deepen their understanding of number because counting is the foundation for number sense.

Students engage in Mathematical Practice 6 (attend to precision) as they work on counting precisely and in order.

**Key vocabulary:**

- counting
- numbers
- one
- two
- three
- four
- five
- six
- seven
- eight
- nine