1.1 Variable and Expressions:

1. Quantity: Anything that can be measured or counted. 1.1 Variable and Expressions: Variable: A symbol, usually a letter, used to represent the value of a variable quantity.

2. Algebraic Expression: A mathematical phrase that includes one or more variables. Numerical Expression: A mathematical phrase involving numbers and operation symbols, but not variables.

3. GOAL:

4. REAL-WORLD: A student writes the word phrase“the quotient of n and 5” to describe the expression 5/n. Describe and correct the student’s error.

5. SOLUTION: Using the definition of quotient = fraction, we see that : 5/n  the quotient of 5 and n. n/5  the quotient of n and 5. Thus the student has the two variables backwards.

6. Write an algebraic expression for the following sentence: “8 minus the product of 9 and r” YOU TRY IT:

7. SOLUTION: Using the basics we learned in Pre-Algebra we know that : Minus  subtraction Product  multiplication 8 minus  8 - Product of 9 and r  9r Therefore: 8 – 9r is the expression.

8. Write an algebraic expression for the following sentence: “3 less than 2 times a number” YOU TRY IT:

9. SOLUTION: Using the basics we learned in Pre-Algebra we know that : 3 Less than subtraction placed at the end of the sentence  - 3 2 times multiplication  2( ), 2∙, 2× A number n to represent any number Therefore: 2n- 3is the expression.

10. VIDEOS: Variables and Expressions Variables: http://www.khanacademy.org/math/algebra/introduction-to-algebra/variable-and-expressions/v/what-is-a-variable Expressions: http://www.khanacademy.org/math/algebra/introduction-to-algebra/variable-and-expressions/v/variables-and-expressions-1

11. CLASSWORK:Page 20-22: Problems: 1, 3, 5, 6, 7, 10, 24 33, 37, 46, 56.