Evaluating Algebraic Expressions 4-8 The Real Numbers Rational and Irrational Numbers.

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Evaluating Algebraic Expressions 4-8 The Real Numbers Rational and Irrational Numbers

Transcript of Evaluating Algebraic Expressions 4-8 The Real Numbers Rational and Irrational Numbers.

Page 1: Evaluating Algebraic Expressions 4-8 The Real Numbers Rational and Irrational Numbers.

Evaluating Algebraic Expressions

4-8 The Real Numbers

Rational and Irrational Numbers

Page 2: Evaluating Algebraic Expressions 4-8 The Real Numbers Rational and Irrational Numbers.

Evaluating Algebraic Expressions

4-8 The Real Numbers

How do I distinguish between How do I distinguish between rational and irrational rational and irrational

numbers?numbers?

Rational and Rational and Irrational Numbers Irrational Numbers Essential QuestionEssential Question

Page 3: Evaluating Algebraic Expressions 4-8 The Real Numbers Rational and Irrational Numbers.

Evaluating Algebraic Expressions

4-8 The Real Numbers

real numberirrational number

Vocabulary

Page 4: Evaluating Algebraic Expressions 4-8 The Real Numbers Rational and Irrational Numbers.

Evaluating Algebraic Expressions

4-8 The Real Numbers

The set of real numbers is all numbers that can be written on a number line. It consists of the set of rational numbers and the set of irrational numbers.

Irrational numbersRational numbers

Real Numbers

Integers

Wholenumbers

Page 5: Evaluating Algebraic Expressions 4-8 The Real Numbers Rational and Irrational Numbers.

Evaluating Algebraic Expressions

4-8 The Real Numbers

Recall that rational numbers can be written as the quotient of two integers (a fraction) or as either terminating or repeating decimals.

3 = 3.84 5

= 0.623

1.44 = 1.2

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Evaluating Algebraic Expressions

4-8 The Real Numbers

A repeating decimal may not appear to repeat on a calculator, because calculators show a finite number of digits.

Caution!

Irrational numbers can 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. For example, 2 is not a perfect square, so 2 is irrational.

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Evaluating Algebraic Expressions

4-8 The Real NumbersMake a Venn Diagram that displays the following sets of numbers: Reals, Rationals, Irrationals, Integers, Wholes, and Naturals.

Naturals1, 2, 3...

Wholes0

Integers-3 -19

Rationals

2

36

1

4

-2.65

Irrationals2

Reals

Page 8: Evaluating Algebraic Expressions 4-8 The Real Numbers Rational and Irrational Numbers.

Evaluating Algebraic Expressions

4-8 The Real NumbersAdditional Example 1: Classifying Real Numbers

Write all classifications that apply to each number.

5 is a whole number that is not a perfect square.

5

irrational, real

–12.75 is a terminating decimal.–12.75rational, real

16 2

whole, integer, rational, real

= = 24 2

16 2

A.

B.

C.

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Evaluating Algebraic Expressions

4-8 The Real NumbersCheck It Out! Example 1

Write all classifications that apply to each number.

9

whole, integer, rational, real

–35.9 is a terminating decimal.–35.9rational, real

81 3

whole, integer, rational, real

= = 39 3

81 3

A.

B.

C.

9 = 3

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Evaluating Algebraic Expressions

4-8 The Real Numbers

A fraction with a denominator of 0 is undefined because you cannot divide by zero. So it is not a number at all.

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Evaluating Algebraic Expressions

4-8 The Real Numbers

State if each number is rational, irrational, or not a real number.

21

irrational

0 3

rational

0 3

= 0

Additional Example 2: Determining the Classification of All Numbers

A.

B.

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Evaluating Algebraic Expressions

4-8 The Real Numbers

not a real number

Additional Example 2: Determining the Classification of All Numbers

4 0

C.

State if each number is rational, irrational, or not a real number.

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Evaluating Algebraic Expressions

4-8 The Real Numbers

23 is a whole number that is not a perfect square.

23

irrational

9 0

undefined, so not a real number

Check It Out! Example 2

A.

B.

State if each number is rational, irrational, or not a real number.

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Evaluating Algebraic Expressions

4-8 The Real Numbers

64 81

rational

8 9

=8 9

64 81

C.

Check It Out! Example 2

State if each number is rational, irrational, or not a real number.