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

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

GOAL:

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.

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.

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

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.

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

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

VIDEOS: Variables and Expressions Variables: duction-to-algebra/variable-and- expressions/v/what-is-a-variable duction-to-algebra/variable-and- expressions/v/variables-and-expressions-1 Expressions:

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