Post on 11-Jan-2016
Rational Numbers
Math 8
OBJECTIVE:-You will be able to identify rational numbers
-You will be able to write fractions as decimals
Word Watch:-rational number-terminating decimals-repeating decimals
PICK YOUR BRAIN!!
• What is a whole number?Positive whole numbers starting with 0. Ex: 0,1,2,3,4, etc.
• What is an integer?The numbers …, -4, -3, -2, -1, 0, 1, 2, 3, 4…Consists of negative #’s, zero, & positive #’s.
A rational number is a number that can be written as where a and b are integers.
(In other words, it can be written as a fraction.)
Let’s look at the relationship among whole numbers, integers, and rational numbers.
ab
Rational #’s
Integers
Whole #’s
0.8
5.2
-10-6
5
12
-1.44
23
1
813
0
-4
_
2
12
49
Identify Rational NumbersShow that the number is rational by writing it as
a fraction.
a) 6
b)
c) 0.75
d)
35
13
-
-2
61
-35
75100
34
-73
=
==
=
=
YOUR TURN!! Show that each number is rational by writing it
in form.
a) 2.5
b) -1
c) -0.8
d)
ab
58
52
-11
-810
-45
58
=
=
= =
=
Writing Fractions as Decimals
Write as a decimal720
20)7.00______.0 3
60100____
5
1000
Write zeros in dividend as placeholders.
remainder is zero
Write 3 as a decimal58
What can you tell me about the 3?
3 is a whole number. It will be on the left side of the decimal point.
8)5.000______0.6
4820
2
1640
5
400
3 + 0.625 = 3.625
YOUR TURN
Write as a decimal
Write 3 as a decimal
310
45
0.3
3.8
VOCAB
When a long division problem results in a remainder of 0, the quotient is a terminating decimal.
Repeating decimal: where one of more digits repeat without end. Can be written with a bar over the digit(s) that repeat. (bar notation)
Writing Fractions as Repeating Decimals
Write as a decimal53
3)5.000______1.
320
6
1820
6
18
6
20
The digit 6 keeps repeating!
The remainder will never be zero
53
= 1.6_
Write as a decimal1333
33)13.000_________0. 3
99310
9
297130
3
99310
9 The digits 3 and 9 keep repeating
Remainder will never be zero
YOUR TURN
Write as a decimal79
0.7__