2 2 rational numbers trout09
TRANSCRIPT
2.2 Rational Numbers
Objectives:
1. To show that a number is a rational #
2. To graph rational #’s
3. To compare rational #’s using < or >
Classes of Numbers
Rational Numbers Comes from the word “ratio” Any number that can be
expressed as the ratio of two integers is a fraction
A fraction is a rational number
Turn any whole # into a fraction by….
Putting it over 1
Ex 1: Write as the ratio of two integers
3
1−
3−
Ex 2: Write as a ratio of two integers:7
etcor2
14
1
7
Any terminating or repeating decimal can be written as a fraction
It there is 1 decimal place …. put the number over
10 2 decimal places … put over 100 3 decimal places … put over 1000
****Remember to REDUCE*******
Ex 3: Write as the ratio of two integers
92
10=
9.2
Ex 4: Write as a ratio of two integers:0.7
10
7
Ex 5: Write as a ratio of two integers:4.5
2
9
10
45or
Ex 6: Write the following number as a ratio of two integers:-9.23
923
100
−
Write a mixed number as a ratio of two integers by…
Turning it into an improper fraction
Ex 7: Write 7 ½ as a ratio of two integers
15
2
NegativeRational Numbers“Negative three-fourths”
4
3−4
3−4
3
−
Graphing Fractions on the # line
Turn improper fractions to mix numbers Find the 2 whole numbers the fraction is
in between and put a dot between those two whole numbers
Ex 8: Graph on the Number Line
0 42-6 -4 -2 6
2
5
Ex 9: Graph on the Number Line
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5.4−
Comparing Decimals
Compare each place value
Ex 10: Comparing Rational Numbers Using “< “ and “>”
1.38 � 1.83<
Ex 11: Comparing Rational Numbers Using “< “ and “>”
� >545.0 543.0
Comparing Fractions
If they have the same denominator compare numerators
If they have different denominators use the heart method
Heart Method
Cross multiply and bring product down Compare the product using < or >
Ex 12: Comparing Rational Numbers Using “< “ and “>”
� 4
3
8
5
Cross multiply and compare their products
Ex 13: Compare Using < or >
2
3
− 4
5
−
Ex 14: Write the rational orders from least to greatest
2 1 3 5 3 1, , , , ,
3 2 4 6 8 6
− − −
Density Property
Between any two rational numbers there is another rational number
Ex 15: Find a number between
1 2
3 3and
Ex 16: Find a number in between0.45 and 0.46
Assignment:
Page 61 (2-38) even
0 42-6 -4 -2 6