Lesson objective: Understand that representing a number in different ways (including base ten numerals, number names, and expanded form) does not change its value.

Students bring prior knowledge that the three digits of a three-digit number represent the amount of hundreds, tens, and ones from 2.NBT.A.1. This prior knowledge is extended to writing the name of a number using expanded form and number name form. A conceptual challenge students may encounter is writing a number in standard form after seeing it represented in expanded form first.

The concept is developed through work with base ten blocks and other manipulatives, which help students to decompose each number into hundreds, tens, and ones.

This work helps students deepen their understanding of equivalence because they are able to see that we can represent the same number in a variety of ways.

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they apply prior knowledge of place value and look for patterns in how we name numbers.

**Key vocabulary:**

- place value
- number name form
- word form
- expanded notation
- decompose

**Special materials needed:**

- base ten blocks to represent the number 412 for each student or each pair of students

- base ten blocks or another manipulatives to represent 137 worms for each student or each pair of students