Day 1- Rational Numbers

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Pre-Algebra

Number Systems

Notes

Name_____________________

Teacher___________________

Period____________________

Day 1- Rational Numbers

A rational number is any real number that can be expressed as the ratio of two integers a

, where b is not equal to zero. b

Examples:

A rational number can be expanded so that the decimals either repeat or terminate. In order to convert a fraction to a repeating decimal, use long division and divide the numerator by the denominator.

Class Examples:

1.) Determine if 5

12 is a rational number and convert it to a decimal.

2.) Determine if 3

8 is a rational number and convert it to a decimal.

3.) Determine if 

3

2

5

is a rational number and convert it to a decimal.

Some square roots are also rational. Any number that has a whole-number square root is a perfect square.

Examples:

All rational numbers can be represented on a number line. To plot rational numbers on a number line, first convert them to the same form.

Class Examples:

4.) Plot and label a point for each rational number below on the number line.

2

2

,

1

3

4

, 

0 .

25

,

4

,

1

9

,

72 .

5 %

-1 0 1 2

5.) Plot and label a point for each rational number below on the number line.

4

15

, 6

3

, 

2

1

4

,

9

,

65 %

, 

1 .

75

-3 -2 -1 0 1 2 3

Day 2- Irrational Numbers

An irrational number is any real number that cannot be expressed as the ratio of two integers a

, where b is not equal to zero. An irrational number can be b expressed as infinite, non-repeating decimal.

Class Examples:

1.) The value of the number pi ( irrational number.

 ) is 3.1459265358… Explain why  is an

The square roots of positive numbers that are not perfect squares are also irrational. You can estimate the value of a square root by deciding which two perfect squares it lies between and then using guess and check to estimate its value more precisely.

2.) Explain why

2 is irrational. Then estimate its value.

3.) Graph the approximate location of

34

on a number line.

4.) Estimate the value of

2 10

5.) Estimate the value of  2 .

.

6.) Estimate the value of

18

.

2

7.) The area of a square is 67 square meters. Find the exact length, in meters, of one side of the square then graph the value on the number line.

Day 3- Compare and Order Rational and Irrational Numbers

Sometimes, you may need to compare or order rational and irrational numbers. The symbols below will help you do this:

> means “is greater than”

< means “is less than”

= means “is equal to”

To compare rational and irrational numbers convert the numbers to decimal form.

Then compare the digits to determine which is greater.

Class Examples:

1.) Which symbol (< , > , =) makes this sentences true?

7.745966…

59

2.) Order the numbers below from least to greatest. Graph on the number line below.

28 %

, 

2

1

2

,

2

7

, 

9

-3 -2 -1 0 1 2 3

3.) Order the following numbers from least to greatest.

 ,

3

1

3

,

14

4.) Order the following numbers from least to greatest.

1

9

,

5

, 

0 .

8

,

3 .

5

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