REAL NUMBERS (as opposed to fake numbers?)
Objective • Identify the parts of the Real Number System • Define rational and irrational numbers • Classify numbers as rational or irrational
Real Numbers Real Numbers are every number. Therefore, any number that you can find on the number line. Real Numbers have two categories.
What does it Mean? • The number line goes on forever. • Every point on the line is a REAL number. • There are no gaps on the number line. • Between the whole numbers and the fractions there are numbers that are decimals but they don’t terminate and are not recurring decimals. They go on forever.
Real Numbers REAL NUMBERS 154,769,852,354 1.333 -5,632.1010101256849765… -8 61 π 49% 549.23789
Two Kinds of Real Numbers • Rational Numbers • Irrational Numbers
Rational Numbers • A rational number is a real number that can be written as a fraction. • A rational number written in decimal form is terminating or repeating.
16 1/2 3.56 -8 1.3333… - 3/4 Examples of Rational Numbers
Integers One of the subsets of rational numbers
What are integers? • Integers are the whole numbers and their opposites. • Examples of integers are 6 -12 0 186 -934
Integers are rational numbers because they can be written as fraction with 1 as the denominator.
Types of Integers • Natural Numbers(N): Natural Numbers are counting numbers from 1,2,3,4,5,................N = {1,2,3,4,5,................} • Whole Numbers (W): Whole numbers are natural numbers including zero. They are 0,1,2,3,4,5,...............W = {0,1,2,3,4,5,..............} W = 0 + N
REAL NUMBERS NATURAL Numbers WHOLE Numbers IRRATIONAL Numbers INTEGERS RATIONAL Numbers
Irrational Numbers • An irrational number is a number that cannot be written as a fraction of two integers. • Irrational numbers written as decimals are non-terminating and non-repeating.
Caution! A repeating decimal may not appear to repeat on a calculator, because calculators show a finite number of digits. Irrational numberscan be written only as decimals that do not terminate or repeat. They cannot be written as the quotient of two integers. If a whole number is not a perfect square, then its square root is an irrational number.
Pi Examples of Irrational Numbers Square roots of non-perfect “squares” √4 is not irrational because it equals 2 which is rational
Try this! a) Irrational b) Irrational c) Rational d) Rational e) Irrational
16 2 4 2 = = 2 Additional Example 1: Classifying Real Numbers Write all classifications that apply to each number. A. 5 is a whole number that is not a perfect square. 5 irrational, real B. –12.75 –12.75 is a terminating decimal. rational, real 16 2 C. whole, integer, rational, real
A fraction with a denominator of 0 is undefined because you cannot divide by zero. So it is not a number at all.
0 3 = 0 Additional Example 2: Determining the Classification of All Numbers State if each number is rational, irrational, or not a real number. A. 21 irrational 0 3 B. rational
Additional Example 2: Determining the Classification of All Numbers State if each number is rational, irrational, or not a real number. 4 0 C. not a real number
Bell Ringer 8-29-12 • Copy the questions and write your answer. • What category does every number on the number line fit into? • What are the two kinds of numbers in this big category? • What is another name for the counting numbers?
Objective • Compare rational and irrational numbers • Order rational and irrational numbers on a number line
Comparing and Ordering Numbers Steps: • Convert all numbers to the same form • Use the number line to help.
Practice < < >
Example • Order these numbers from least to greatest. ¹/₄, 75%, .04, 10%, ⁹/₇ ¹/₄ becomes 0.25 75% becomes 0.75 0.04 stays 0.04 10% becomes 0.10 ⁹/₇ becomes 1.2857142… Answer: 0.04, 10%, ¹/₄, 75%, ⁹/₇
Practice Order these from least to greatest:
Objectives • Identify the rules associated with computing with integers. • Compute with integers
1) (-4) + 8 = Examples: Use the number line if necessary. 4 2) (-1) + (-3) = -4 3) 5 + (-7) = -2
Addition Rule 1) When the signs are the same, ADD and keep the sign. (-2) + (-4) = -6 • When the signs are different, SUBTRACT and use the sign of the larger number. (-2) + 4 = 2 2 + (-4) = -2
Answer Now -1 + 3 = ? • -4 • -2 • 2 • 4
Answer Now -6 + (-3) = ? • -9 • -3 • 3 • 9
The additive inverses(or opposites) of two numbers add to equal zero. -3 Proof: 3 + (-3) = 0 We will use the additive inverses for subtraction problems. Example: The additive inverse of 3 is
When subtracting, change the subtraction to adding the opposite and then follow your addition rule. Example #1: - 4 - (-7) - 4+ (+7) Diff. Signs --> Subtract and use larger sign. 3 Example #2: - 3 - 7 - 3+ (-7) Same Signs --> Add and keep the sign. -10
Answer Now Which is equivalent to-12 – (-3)? • 12 + 3 • -12 + 3 • -12 - 3 • 12 - 3
Answer Now 7 – (-2) = ? • -9 • -5 • 5 • 9
Review 1) If the problem is addition, follow your addition rule.2) If the problem is subtraction, change subtraction to adding the opposite and then follow the addition rule.
State the rule for multiplying and dividing integers…. If the signs are the same, If the signs are different, the answer will be negative. the answer will be positive.
Different Signs Negative Answer What’s The Rule? 1. -8 * 3 4. 6 ÷ (-3) -24 -2 Start inside ( ) first 2. -2 * -6 5. - (20/-5) 12 - (-4) Same Signs Positive Answer 4 3. (-3)(6)(1) (-18)(1) 6. (-40) -18 (-5) Just take Two at a time 8
7. At midnight the temperature is 8°C. If the temperature rises 4°C per hour, what is the temperature at 6 am? How much does the temperature rise each hour? How long Is it from Midnight to 6 am? +4 degrees 6 hours (6 hours)(4 degrees per hour) Add this to the original temp. = 24 degrees 8° + 24° = 32°C
8. A deep-sea diver must move up or down in the water in short steps in order to avoid getting a physical condition called the bends. Suppose a diver moves up to the surface in five steps of 11 feet. Represent her total movements as a product of integers, and find the product. Multiply What does This mean? (11 feet) (5 steps) (55 feet) 5 * 11 = 55
