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Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
NS1.1 Compare and order positive and negative fractions, decimals, and mixed numbers and place them on a number line.Also covered: NS2.4
California Standards
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
VOCABULARY CARD
• Rational Number
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Which is greater, or ?79
29
To compare fractions with the same denominator, just compare the numerators.
79 > 2
9 because 7 > 2.= 7
9
=29
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
One way to compare fractions with unlike denominators is to use models. For example,
the models show that < . 38
12
Another way to compare fractions with unlike denominators is to first write equivalent fractions with common denominators. Then compare the fractions.
38= 1
2=
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Compare the fractions. Write < or >.
Teacher Example 1A: Comparing Fractions
79
58
The LCM of the denominators 9 and 8 is 72.
79 = 7 8
9 8 = 5672
58 = 5 9
8 9 = 4572
5672 > 45
72 , and so . 79 > 5
8
Write equivalent fractions with 72 as the denominator.
Compare the numerators.
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Teacher Example 1B: Comparing Fractions
Compare the fractions. Write < or >.
25
37
– –
25– = –2 7
5 7= –14
3537– = –3 5
7 5 =–15 35
– 1435 > – 15
35 , and so – > .25
– 37
Write equivalent fractions with 35 as the denominator.Put the negative signs in the numerators.
Both fractions can be written with a denominator of 35.
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
A fraction less than 0, such as , can be
written as , , or .
Helpful Hint!
2 52
52 5 2
5
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Compare the fractions. Write < or >.
56
78
The LCM of the denominators 6 and 8 is 48.
56 = 5 8
6 8 = 4048
78 = 7 6
8 6 = 4248
4048 < 42
48 , and so . 56 < 7
8
Write equivalent fractions with 48 as the denominator.
Student Practice 1A:
Compare the numerators.
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Compare the fractions. Write < or >.
68
57
– –
68– = –6 7
8 7= –42
5657– = –5 8
7 8 =–40 56
– 4256 < – 40
56 , and so – < .68
– 57
Write equivalent fractions with 56 as the denominator.Put the negative signs in the numerators.
Student Practice 1B:
Both fractions can be written with a denominator of 56.
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
To compare decimals, line up the decimal points and compare digits from left to right until you find the place where the digits are different.
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Compare the decimals. Write < or >.
Teacher Example 2A: Comparing Decimals
0.427 0.425
0.427
0.425
Since 0.007 > 0.005, 0.427 > 0.425.
Line up the decimal points.The tenths and hundredths arethe same.Compare the thousandths:
7
5
7 > 5.
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Compare the decimals. Write < or >.
Teacher Example 2B:
0.73 0.734
0.733…
0.734
Line up the decimal points.
The tenths and hundredths arethe same.
Compare the thousandths:
3
4
3 < 4.
0.73 =_
Since 0.003 is < 0.004, 0.73 < 0.734.
0.73 is a repeating decimal.
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Compare the decimals. Write < or >.
0.535 0.538
0.535
0.538
Since 0.005 < 0.008, 0.535 < 0.538.
Line up the decimal points.The tenths and hundredths arethe same.Compare the thousandths:
5
8
5 < 8.
Student Practice 2A:
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Compare the decimals. Write < or >.
Student Practice 2B:
0.334
0.3333…
0.334
Line up the decimal points.The tenths and hundredths arethe same.Compare the thousandths:
3
4
3 < 4.
0.3
Since 0.003 is < 0.004, 0.3 < 0.334.
0.3 = 0.3 is a repeating decimal.
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
A rational number is a number that can be written as a fraction or quotient of integers with a nonzero denominator. When rational numbers are written in a variety of forms, you can compare the numbers by writing them all in the same form.
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
The values on a number line increase as you move from left to right.
Remember!
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Order
Teacher Example 3: Ordering Fractions and Decimals
45
0.93, and 0.9 from least to greatest.,
45 = 0.80
Graph the numbers on a number line.
0 0.2 0.4 0.6 0.8 1
0.93
Write as decimals with the same number of places.
0.93 = 0.93 0.9 = 0.90
0.80 < 0.90 < 0.93 Compare the decimals.
45From least to greatest, the numbers are , 0.9, 0.93.
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Order , 0.84, and 0.7 from least to greatest.
Student Practice 3:
35
35 = 0.60
Graph the numbers on a number line.
0 0.2 0.4 0.6 0.8 1
0.84
Write as decimals with the same number of places.
0.84 = 0.84 0.7 = 0.70
0.60 < 0.70 < 0.84 Compare the decimals.
35
From least to greatest, the numbers are , 0.7, 0.84.
Holt CA Course 1
3-6 Comparing and Ordering Rational Numbers
Lesson Quiz
Compare the fractions. Write > or <.
1. 2.
Compare the decimals. Write < or >.
3. 0.32 and 0.312
>
37
and 410
58 and
23
<>
56
0.8, 0.826, 56
4. Order , 0.8, 0.826 from least to greatest.
Graph the numbers on a number line.
0.80 0.81 0.82 0.83 0.84 0.85
0.8 0.82656
