Lesson 3: Evaluating Algebraic Expressions

What does it mean to evaluate an expression?
Why is the order of operations used to evaluate expressions?

Evaluate
solution

Evaluating algebraic expressions involves substituting given values for variables and performing the indicated operations. To ensure accuracy and consistency, it's crucial to follow these standards

Lesson Description In this section, students transition from seeing variables as abstract symbols to seeing them as "placeholders" for numbers.
The lesson covers: The Substitution Principle: Properly replacing every instance of a variable with a given value using parentheses to maintain structural integrity. Handling Negatives: Special emphasis on squaring negative numbers (e.g., the difference between -x^2 and (-x)^2 when x = 3).Multi-Variable Expressions: Evaluating formulas that contain two or more variables, such as 3x - 2y + 5.Real-World Formulas: Applying evaluation skills to common formulas like Perimeter (P = 2l + 2w), Interest (I = Prt), or Temperature conversion.
Purpose: The purpose of this lesson is to establish precision and procedural fluency. In Mat095, many errors in later chapters (like the Quadratic Formula) stem from improper substitution. By mastering evaluation now, students: Learn to verify if a number is a solution to an equation. Gain confidence in using the Order of Operations (PEMDAS) within a variable-rich environment.Understand that an algebraic expression represents a set of infinite possibilities, which "freezes" into a single value once the variable is defined.
DOK Level: 1 & 2Level 1 (Recall & Reproduction): Students will perform simple substitutions into linear expressions (e.g., evaluate x + 10 for x = 5).Level 2 (Skills & Concepts): Students will evaluate complex expressions involving exponents, grouping symbols, and multiple variables, requiring careful adherence to the order of operations.

class and online work

sections 1.3  pg 36 "you try' and practice problems