Lesson 2: Like Terms

When is an expression in its simplest form?

Like Terms
Simplest Form

Interpret expressions that represent a quantity in terms of its context.
A.SSE.1a
Interpret parts of an expression, such as terms, factors, and coefficients.
A.SSE.2
Use the structure of an expression to identify ways to rewrite it

Lesson Description: This lesson focuses on the criteria required to combine terms and the mechanics of the Distributive Property. Key components include: Defining "Like Terms": Understanding that terms must have the exact same variables raised to the exact same exponents to be combined (e.g., 3x^2 and 5x^2 are like terms, but 3x and 3x^2 are not).
The Distributive Property: Applying a(b + c) = ab + ac to "unlock" terms inside parentheses.
Combining Coefficients: Learning that when combining like terms, we add or subtract the coefficients while leaving the variable part unchanged. Simplifying Multi-Step Expressions: Handling expressions that require both distribution and combining terms (e.g., 3(x + 4) - 2x).
Purpose: The purpose of this lesson is to teach efficiency and reduction. In algebra, we rarely want to work with a "long" expression if a "short" one will do. By mastering like terms, students learn to declutter mathematical statements, which is a prerequisite for solving equations in Unit 3. It also reinforces the concept that variables represent specific "kinds" of quantities that cannot be mixed arbitrarily.
DOK Level: 2DOK 2 (Skill/Concept): This section moves beyond simple recall. Students must classify terms as like or unlike, apply the Distributive Property, and execute a multi-step process to reach a simplified form. It requires identifying patterns and making decisions about which operations to perform first.

Class and online work

Section 2.2 - You Try Page 58
Problems a and b

Practice Problems

Textbook with guided class notes and videos