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This math lesson covers the concepts of reducing fractions to lowest terms, performing addition/subtraction, and multiplication/division with fractions. Examples and exercises are provided to help understand these operations.
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Math 105 – 5A Mr. Chris Staat
Section 1.2 Getting Started: Reviewing Prealgebra
Operations With Fractions • We should be able to perform the following operations on fractions: • Reduce to lowest terms • Addition/Subtraction • Multiplication/Division We should be able to do these abstractly and in specific applied situations.
Lowest Terms • A fraction is in lowest terms if the numerator and the denominator share no common factor. • What does this mean?
Lowest Terms • A fraction is in lowest terms if the numerator and the denominator share no common factor. • For Example: and These fractions are called equivalent because they have the same lowest terms form.
Addition/Subtraction • In order to add/subtract fractions, they must have common denominators. • So first we rewrite each fraction as an equivalent fraction with the same denominator. • Then we add/subtract the numerators. • Then write the result in lowest terms.
Addition/Subtraction • For example:
Multiplication • In order to multiply fractions: • Firstmultiply the numerators together and then multiply the denominators together. • Then rewrite the answer in lowest terms.
Multiplication • For example:
Multiplication • For example:
Division • In order to divide fractions: • First, rewrite the division as multiplication by the reciprocal • Then multiply as explained earlier. • Then rewrite the answer in lowest terms.
Division • For example:
Division • For example:
Exercise 1a A school has two pathways through the math program. Two-thirds of students take the first path while the rest take the second path. During one semester, 3/4 of the students who follow the first path pass the program while 9/10 of the students who follow the second path pass the program. What fraction of students take the first path and pass?
Exercise 1a A school has two pathways through the math program. Two-thirds of students take the first path while the rest take the second path. During one semester, 3/4 of the students who follow the first path pass the program while 9/10 of the students who follow the second path pass the program. What fraction of students take the first path and pass?
Exercise 1b A school has two pathways through the math program. Two-thirds of students take the first path while the rest take the second path. During one semester, 3/4 of the students who follow the first path pass the program while 9/10 of the students who follow the second path pass the program. What fraction of students take the second path and pass?
Exercise 1c A school has two pathways through the math program. Two-thirds of students take the first path while the rest take the second path. During one semester, 3/4 of the students who follow the first path pass the program while 9/10 of the students who follow the second path pass the program. What fraction of students pass?
Exercise 1c A school has two pathways through the math program. Two-thirds of students take the first path while the rest take the second path. During one semester, 3/4 of the students who follow the first path pass the program while 9/10 of the students who follow the second path pass the program. What fraction of students pass?
Exercise 2 A cookie recipe calls for 2/3 cup of flour per batch of cookies, and each batch makes 2 dozen cookies. How many cookies can you make if you have 10 cups of flour and want to use all of the flour?
Exercise 2 A cookie recipe calls for 2/3 cup of flour per batch of cookies, and each batch makes 2 dozen cookies. How many cookies can you make if you have 10 cups of flour and want to use all of the flour?
Venn Diagrams • A Venn diagram is a graph that helps compare and contrast sets. Each set is represented by a circle, and circles that have elements in common overlap. The circles are usually enclosed in a box which represents a larger set where elements that do not belong within either circle.
Venn Diagrams • For Example E F 1 = In E, not in F 2 = in F, not in E 3 = in both E and F 4 = in neither E nor F 3 1 2 4
Exercise 3 In a freshman class of 2000 students at a certain college, 1250 are taking either a developmental math or reading class. Of these 1250 students, 726 are taking both a developmental math class and a developmental reading class, and 437 are taking only a developmental math class. Construct a Venn diagram for this scenario and describe what each number represents.