Adding Like Fractions

Main Idea/Vocabulary like fractions Add and subtract fractions with like denominators.

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Example 1 Add Like Fractions Answer: Add the numerators. The denominators are the same.

1.A 2.B 3.C 4.D Example 1 A. B. C. D.

Example 2 Subtract Like Fractions Answer: Subtract the numerators. The denominators are the same.

1.A 2.B 3.C 4.D Example 2 A. B. C. D.

Example 3 Add Mixed Numbers Add the whole numbers and fractions separately. Answer:

1.A 2.B 3.C 4.D Example 3 A. B. C. D.

Example 4 Estimate 64 – 54 = 10 Subtract Mixed Numbers HEIGHTS In the United States, the average height of a 9-year-old girl is inches. The average height of a 16-year-old girl is inches. How much does an average girl grow from age 9 to age 16?

Example 4 Write the mixed numbers as improper fractions. Subtract Mixed Numbers Answer: Subtract the numerators. The denominators are the same.

1.A 2.B 3.C 4.D Example 4 A.B. C.D. HEIGHTS Ainsley was inches tall when she was 4 years old. When she was 10 years old, she was inches tall. How much did she grow between the ages of 4 and 10?

When adding or subtracting fractions that have like or same denominators, then one simply adds or subtracts the numerators and keeps the denominator the same throughout. The numerators are in red and the denominators are in blue. Also you should simplify or reduce your fraction in the last step. The final answer is circled in purple = 5 5 reduces to 1 2 Adding and Subtracting Fractions with Like Denominators

Adding Unlike Fractions

Main Idea/Vocabulary unlike fractions Add and subtract fractions with unlike denominators.

Main Idea/Vocabulary

least common denominator (LCD) Given several denominators, the smallest expression that is divisible by all the denominators is called the least common denominator.

Example 1 Add and Subtract Unlike Fractions The LCD is 2 ● 2 ● 2 or 8. Rename the fractions using the LCD. Add the numerators. Simplify.

Example 1 Add and Subtract Unlike Fractions Answer:

1.A 2.B 3.C 4.D Example 1 A. B. C. D.

Example 2 Add and Subtract Unlike Fractions 96 = 3 ● 2 5, 128 = 2 7. The LCD is 3 ● 2 7 or 384. Rename using the LCD. Add the numerators.

Example 2 Add and Subtract Unlike Fractions Answer: Simplify.

1.A 2.B 3.C 4.D Example 2 Subtract. Write in simplest form. A. B. C. D.

Example 3 Add and Subtract Mixed Numbers Write the mixed numbers as fractions.

Example 3 Add and Subtract Mixed Numbers Add the numerators. Simplify. Answer:

1.A 2.B 3.C 4.D Example 3 A. B. C. D.

Example 4 A B C D EXAMPLE During January, Nikki watched television hours the first week, hours the second week, hours the third week, and hours the fourth week. How much time did she watch television during the 4-week period?

Example 4 Read the Item You need to find the sum of four mixed numbers. Solve the Item It would take some time to change each of the fractions to ones with a common denominator. However, notice that all four of the numbers are about 2. Since 2 x 4 = 8, the answer will be about 8. Notice that only one of the choices is close to 8. Answer: B

1.A 2.B 3.C 4.D Example 4 A.B. C.D. During July, Carsten watched television hours the first week, hours the second week, and hours the third week. How much time did she watch television during the 3-week period?

Adding and Subtracting Fractions with Unlike Denominators When adding or subtracting fractions with unlike denominators, it is necessary to change or convert the fractions to equivalent fractions with like or same denominators. The numerators are red and the denominators are blue. The final reduced answer is circled in purple =? 4 5 converts to = 5 5 reduces to 1 2