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Fractions and Rational Expressions. Name the fraction represented by a shaded region. Graph fractions on a number line. Simplify fractions. Write equivalent fractions. Use, <, >, or = to write a true statement. Write improper fractions as mixed numbers.
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Fractions and Rational Expressions Name the fraction represented by a shaded region. Graph fractions on a number line. Simplify fractions. Write equivalent fractions. Use, <, >, or = to write a true statement. Write improper fractions as mixed numbers. Write mixed numbers as improper fractions. 5.1
Objective 1 Name the fraction represented by a shaded region.
Definition Fraction: A number that describes a part of a whole. We can describe the three lots that have been sold out of the five total lots using the fraction , which is read “three fifths.” Fractions have numerators (the number 3) and denominators (the number 5 in this example).
Definitions Numerator: The number written in the top position of the fraction. Denominator: The number written in the bottom position of a fraction. The denominator, 5, is the number of equal-sized divisions. The numerator, 3, is the number of those division we are interested in working with. Numerator Denominator
Definition Rational number: A number that can be expressed in the form , where a and b are integers and b ≠ 0. …is a rational number because 3 and 5 are integers and the denominator, 5, is not 0.
Example 1 Name the fraction represented by the shaded region. a. b.
Example 2 In a group of 35 people at a conference, 17 are wearing glasses. What fraction of the people at the conference are wearing glasses? What fraction are not wearing glasses?
Objective 2 Graph fractions on a number line.
Graph the fraction on a number line. Example 3 a. 0 1
Objective 3 Simplify fractions.
Definitions Simplify: The process of writing an equivalent expression with fewer symbols or smaller numbers. Simplest form: An equivalent expression written with the fewest symbols and the smallest numbers possible.
Example 4 Simplify.
Rule If the denominator of a fraction is 1, the fraction can be simplified to the numerator. In math language:
Example 5 Simplify.
Rule If the numerator of a fraction is 0, and the denominator is any number other than 0, the fraction can be simplified to 0. In math language:
Example 6 Simplify.
Rule If the denominator of a fraction is 0, and the numerator is any number other than 0, we say the fraction is undefined. In math language:
Example 7 Simplify.
Rules A fraction with the same nonzero numerator and nonzero denominator can be simplified to 1. In math language: If the numerator and denominator of a fraction are both 0, the fraction is indeterminate. In math language:
Objective 4 Write equivalent fractions.
Definition Equivalent fractions: Fractions that name the same number. 1
Procedure To write an equivalent fraction, multiply or divide both the numerator and denominator by the same nonzero number.
Example 8 Fill in the blank so that the fractions are equivalent.
Objective 5 Use <, >, or = to write a true statement.
We can easily compare fractions with the same denominator. If two fractions don’t have the same denominator, we can draw a picture and compare them. We could also write fractions so that they have a common denominator by using multiples.
Definition Multiple: A number that is evenly divisible by a given number. Multiples of 2 are 2, 4, 6, 8, 10,… Multiples of 3 are 3, 6, 9, 12, 15,… Notice the common multiple for 2 and 3 is 6…it appears in both lists. To upscale 1/2, we multiply numerator and denominator by 3. To upscale 1/3, we, multiply numerator and denominator by 2.
Procedure To compare two fractions: • Write equivalent fractions that have a common denominator. • Compare the numerators of the equivalent fractions.
Example 10 Use <, >, or = to write a true statement. b. a.
Objective 6 Write improper fractions as mixed numbers.
Definition Improper fraction: A fraction in which the absolute value of the numerator is greater than or equal to the absolute value of the denominator.
Definition Mixed number: An integer combined with a fraction When we say combined, we literally mean added. Note: 2 ¼ is read “two and one-forth” and means two wholes plus ¼ of another whole. How does this apply to negative mixed numbers? Note: The negative sign applies to both the integer and the fraction.
Procedure To write an improper fraction as a mixed number: • Divide the denominator into the numerator. • Write the result in the following form.
Example 11 Write the improper fraction as a mixed number. b. a.
Objective 7 Write mixed numbers as improper fractions.
Procedure To write a mixed number as an improper fraction: • Multiply the integer by the denominator. • Add the resulting product to the numerator to find the numerator of the improper fraction. • Keep the same denominator.
Example 13 Write the mixed number as an improper fraction. b. a.