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Write each mixed number as an improper fraction.
Warm Up Write each mixed number as an improper fraction. 1. 1 3. 1 3 4 7 4 7 8 23 8 2. 2 5 6 11 6 1 12 97 12 4. 8
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2-7 Rational Numbers Compare and order positive and negative fractions, decimals, and mixed numbers and place them on a number line.
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A fraction that does not have a zero on the bottom
Rational Number a number that can be written as a fraction or quotient of two integers with a nonzero denominator. A fraction that does not have a zero on the bottom A terminating decimal 2 5 A repeating decimal 0.425 0.73
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7 9 2 9 Which is greater, or ? To compare fractions with the same denominator, just compare the numerators. 7 9 = 7 9 2 9 > because 7 > 2. 2 9 =
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Example 1A: Comparing Fractions
Compare the fractions. Write < or >. 7 9 5 8 The LCM of the denominators 9 and 8 is 72. 7 9 7 8 9 8 56 72 = Write equivalent fractions with 72 as the denominator. = 5 8 5 9 8 9 45 72 = = Compare the numerators. 56 72 > 45 , and so 7 9 > 5 8
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Example 1B: Comparing Fractions
Compare the fractions. Write < or >. 2 5 3 7 – – Both fractions can be written with a denominator of 35. 2 5 –2 7 5 7 –14 35 Write equivalent fractions with 35 as the denominator. Put the negative signs in the numerators. – = = 3 7 –3 5 7 5 –15 35 – = = 14 35 15 35 2 5 3 7 – > – , and so – > –
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A fraction less than 0, such as - , can be
written as - , , or . Helpful Hint! 2 5 -2 5
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Check It Out! Example 2A Compare the fractions. Write < or >. 5 6 7 8 The LCM of the denominators 6 and 8 is 24. 5 6 20 24 Write equivalent fractions with 48 as the denominator. 5 4 6 4 = = 7 8 7 3 8 3 21 24 = = Compare the numerators. 20 24 < 21 , and so 5 6 < 7 8
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Check It Out! Example 2B Compare the fractions. Write < or >. 6 8 5 7 – – Both fractions can be written with a denominator of 56. 6 8 –6 7 8 7 –42 56 Write equivalent fractions with 56 as the denominator. Put the negative signs in the numerators. – = = 5 7 –5 8 7 8 –40 56 – = = 42 56 40 56 6 8 5 7 – < – , and so – < –
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Comparing Decimals 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.
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Example 3A: Comparing Decimals
Compare the decimals. Write < or >. 0.427 0.425 0.427 7 Line up the decimal points. The tenths and hundredths are the same. 0.425 5 Compare the thousandths: 7 > 5. Since > 0.005, >
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Additional Example 3B: Comparing Decimals
Compare the decimals. Write < or >. 0.73 0.734 0.73 = _ 0.733… 3 0.73 is a repeating decimal. Line up the decimal points. 0.734 4 The tenths and hundredths are the same. Compare the thousandths: 3 < 4. Since is < 0.004, 0.73 <
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Check It Out! Example 4A Compare the decimals. Write < or >. 0.535 0.538 0.535 5 Line up the decimal points. The tenths and hundredths are the same. 0.538 8 Compare the thousandths: 5 < 8. Since < 0.008, <
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Check It Out! Example 4B Compare the decimals. Write < or >. 0.3 0.334 0.3 = 0.3333… 3 0.3 is a repeating decimal. Line up the decimal points. The tenths and hundredths are the same. 0.334 4 Compare the thousandths: 3 < 4. Since is < 0.004, 0.3 <
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The values on a number line increase as you move from left to right.
Remember!
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Or treat like money if possible: 80 cents, 90 cents, 93 cents
Additional Example 5: Ordering Fractions and Decimals 4 5 Order , 0.93, and 0.9 from least to greatest. Write as decimals with the same number of places. 4 5 = 0.80 0.93 = 0.93 0.9 = 0.90 Graph the numbers on a number line. 0.93 0.80 < 0.90 < 0.93 Compare the decimals. 4 5 From least to greatest, the numbers are , 0.9, 0.93. Or treat like money if possible: 80 cents, 90 cents, 93 cents
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Or treat like money if possible: 60 cents, 70 cents, 84 cents
Check It Out! Example 6 3 5 Order , 0.84, and 0.7 from least to greatest. Write as decimals with the same number of places. 3 5 = 0.60 0.84 = 0.84 0.7 = 0.70 Graph the numbers on a number line. 0.84 0.60 < 0.70 < 0.84 Compare the decimals. 3 5 From least to greatest, the numbers are , 0.7, 0.84. Or treat like money if possible: 60 cents, 70 cents, 84 cents
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Homework Pg 104 #2-36 evens only
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Choose the greater number. 1.
Lesson Quiz Choose the greater number. 1. Place the numbers in order from least to greatest 3. 0.3, 0.32, 0.312 3 7 4 10 3 7 5 8 2 3 2 3 or 2. or 0.3, 0.312, 0.32 5 6 4. 0.8, 0.826, 5 6 , 0.8, 0.826 5. Dana’s cross-country team is getting ready for a big meet. On Monday they ran 3.7 miles, on Tuesday they ran 3 miles, and on Wednesday they ran miles. On which day did they run the greatest distance? 3 8 11 4 Monday
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