1. YoungMath and Expert Subjects.com Present
Algebra I: Variables

2. Lesson Objectives (A.3a;A.3b):
Define the purpose of Algebra
Define Algebra
Define variable
Define algebraic expression
Define algebraic equation

3. “Algebra looks so hard!”
Why am I learning this?
Algebra is everywhere!
Teaches organization
Simple way of expressing a question to enable you to find the answer faster
Sharpen your reasoning (problem solving) skills
Prepare your for higher learning
“Algebra looks so hard!”

4. What is algebra? Examples:
The part of mathematics in which letters and other symbols are used to represent unknown numbers and quantities in formulas and equations.
Examples:
If there are 4,000 widgets in a mile, how long is a widget (in inches)?
2. If the temperature outside is 25° F, what is the temperature in degrees Celsius?

5. What is the unknown value?
What’s the unknown in example 1? Length of a widget in inches
What is the unknown in example 2? Temperature in degrees Celsius
In algebra, we use variables to represent unknown values.
Variable:
*A symbol (frequently a letter) used to represent an unknown value;
An element, feature, or factor that is liable to vary or change

6. Expressions vs. Equations
Question: What is the difference between a expression and an equation?
Language Arts- phrase and a sentence
Phrase does not convey meaning
Ex: “down the street”
Sentence is complete thought
Ex: “I went down the street.”
Expression is a mathematical “phrase”
Ex:
Equation mathematical “sentence”
Ex: = 7

7. Algebraic Expressions & Equations
Definition: mathematical expressions and equations the use a variable
Example of algebraic expressions:
4x + 7 7y
2 + θ
α / 6σ
Cannot be solved; only simplified if possible
Ex: – b
13- b
Example of algebraic equations:
4x + 7 = 9
7y = 49
2 + θ = 45
α/6σ = 546
Can be solved to determine the value of the variable
Ex: 3x =12
x = 4

8. Lesson Objectives (A.3a;A.3b):
Define the purpose of Algebra
Simple way of expressing a question to enable you to find the answer faster
Define Algebra
The part of mathematics in which letters and other symbols are used to represent unknown numbers and quantities in formulas and equations.
Define variable
A symbol (frequently a letter) used to represent an unknown value
Define algebraic expression
A mathematical “phrase” in which letters and other symbols are used to represent unknown numbers and quantities (Does not convey meaning!)
Define algebraic equation
A mathematical “sentence” in which letters and other symbols are used to represent unknown numbers and quantities (complete thought!)