Algebra I SECTION 2 1 THE REAL NUMBERS

Algebra I SECTION 2. 1 THE REAL NUMBERS AND ABSOLUTE VALUE

Warm-up Evaluate each expression. 190 – 128 ÷ 4 2. 21 – 6 · 3 + 4² 3. 8 · 9 + 7 · 5 4. 2(5 + 8 – 6) + 11 5. 3² · 4 + [9 – (2² - 1)]

Language Math alphabet digits words Nouns, Verbs, Adjectives numbers Natural: 1, 2, 3, …. Whole: 0, 1, 2, 3, … Integers: … -3, -2, -1, 0, 1, 2, 3, … Rational numbers: Any number that can be expressed in the form a/b, where a and b are integers and b ≠ 0 Irrational numbers: Any number that can not be expressed in the form a/b, where a and b are integers and b ≠ 0 Real Number: Any number that is rational or irrational See Diagram p 56 in book

Language Math alphabet digits words Order using the alphabet numbers Order using relational operators: <, >, =, ≤, ≥, ≠ Example: Insert an ordering symbol to make each statement true. a. 5 _____ - 7 b. 1/2 ____ 8/16 c. -4. 8 ____ -4. 7 d. 4⅔ _____ 6 Practice: Try this – top of page 57.

Opposites : any two numbers that lie on opposite sides of 0 and are the same distance from 0. 2 and -2 are opposites Example: a. -(-10) b. –(-3/5) Practice: Try this – Middle of page 57. c. -0 d. –(8. 6 – 1. 5)

Definition of Absolute Value The absolute value a real number x is the distance from x to 0 on a number line. The symbol |x| means the absolute value of x Example: Simplify a. |-8| b. |16| Practice: Try this – top of page 58 If time: Pg 58 Guided practice #4 -15 a Homework: Pg 58 -59 Practice and Apply #16 -60 a c. |7 + 2|