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1-3B Real Numbers & the Number Line

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1 1-3B Real Numbers & the Number Line
Algebra I

2 Sets – defined collection
Element of the set within braces { } Subset – a set consists of elements from the given set

3 What is a real number? Rational & irrational #’s Real Numbers
Rational numbers Integers Whole numbers Natural numbers or counting #’s Irrational numbers

4 Examples of Real numbers
Whole numbers: {0, 1, 2, 3,…} (counting #s) Integers: {…, -2, -1, 0, 1, 2,…} (+ & - whole #s) Rational numbers: a # that can be written as a fraction. When written as a decimal, they terminate or repeat. ½, 1/3, 4/5, 7/9 Irrational numbers: real #s that are not rational such as π or √3. Decimals that do not terminate or repeat.

5 Ex. 1 Classifying Real Numbers
To which subsets of real numbers does each number belong? a.) 12 b.) c.) d.)

6 Ex. 2 What is an inequality that compares the numbers ?

7 Ex. 3 What is the order of from least to greatest?

8 Ex. 4 Graph the real #’s

9 Assignment

10 Properties of Multiplication & Addition
(a, b, & c are real #s) Addition Multiplication Closure a+b is real a*b is real Commutative a+b=b+a ab=ba Associative (a+b)+c=a+(b+c) (ab)c=a(bc) Identity a+0=a, 0+a=a a*1=a, 1*a=a Inverse a+(-a)=0 a*(1/a)=1, a≠0 Distributive a(b+c)=ab+ac (a+b)c=ac+bc

11 Ex. 2 Identify the property that the statement illustrates

12 Additive Inverse (opposite)
ex: a and –a or -5 and 5 Multiplicative Inverse (reciprocal) ex: a and 1/a or -1/3 and -3 Remember: Difference means subtract Quotient means divide

13 Ex. 3 Use properties & definitions of operations to show that
Justify each step.

14 Unit Analysis Examples
685ft + 225ft = 910ft (2.25h) = 135km 3. 45 mi/h

15 Ex. 4 a.) You work 8 hours and earn $60. What is your earning rate?
b.)You buy 18 gallons of gasoline at $2.65 per gallon. What is your total cost?

16 Ex. 4 c.) You drive 90 kilometers per hour. What is your speed in meters per second.

17 1.2 Evaluate & Simplify Algebraic Expressions
Algebra II

18 Base ? Exponent ? Power ?

19 Ex. 1: Evaluate the power (-2)6 = (-2)*(-2)*(-2)*(-2)*(-2)*(-2) = 64
= -(2*2*2*2*2*2) = -64

20 Definitions Variable x Algebraic expression x + 4 Terms Variable term
Constant term coefficient

21 Order of Operations Know these!!
Please Excuse My Dear Aunt Sally ( ) exponents multiply/divide (L to R) add/subtract (L to R)

22 Ex. 2 Evaluate an algebraic expression

23 Ex. 3 You are selling fresh squeezed lemonade at a county fair for $2.50 per glass. You spend $180 to rent the stand and buy the ingredients & supplies you need. Write an expression that shows your profit from selling g glasses of lemonade. Find your profit if you sell 268 glasses of lemonade.

24 Ex. 4 Simplifying by combining like terms
a.) b.) c.) d.)

25 Ex. 5 Simplify a mathematical model
Yesterday, a store sold 60 recordable DVD’s. The Samsung DVD’s sell for $15 each, and the Verbatim DVD’s sell for $12 each. Write and simplify an expression that represents the store’s total income for the DVD sales yesterday if x represents the number of Samsung DVD’s sold. Then find the total income if 38 of the 60 DVD’s were Samsung.

26 Assignment

27 Ex: Simplify the expression.
6m2 – 12m – 7m2 = -m2 – 12m 3(x-2) – 5(x-8) = 3x – 6 – 5x +40 = -2x + 34


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