Lesson objective: Recognize the amount of tens and ones in a two-digit number.

Students bring prior knowledge of place value from K.NBT.A.1. This prior knowledge is extended to larger two-digit numbers as students recognize the amount of tens and ones that compose two-digit numbers beyond 20. A conceptual challenge students may encounter is distinguishing between the tens place and the ones place.

The concept is developed through work with place value chart, which helps students to develop their understanding of the composition of two-digit numbers.

This work helps students deepen their understanding of numbers because it strengthens their concept of number composition.

Students engage in Mathematical Practice 7 (Students continue to explore the structure of place value) as they compose and decompose two-digit numbers using a variety of visual tools and manipulatives.

**Key vocabulary:**

- digit
- ones place
- tens place

**Special materials needed:**

- base ten blocks
- place value chart