Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Chapter 2 Multiplying and Dividing Fractions

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. 2.4 Multiplying Fractions and Mixed Numbers

Martin-Gay, Developmental Mathematics, 2e 33 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Multiplying Fractions To multiply two fractions, multiply the numerators and multiply the denominators. If a, b, c, and d represent positive whole numbers we have

Martin-Gay, Developmental Mathematics, 2e 44 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Examples Multiply. a. b. c.

Martin-Gay, Developmental Mathematics, 2e 55 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Examples Multiply and simplify. a. b.

Martin-Gay, Developmental Mathematics, 2e 66 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Multiplying Fractions and Mixed Numbers or Whole Numbers Multiplying Fractions and Mixed Numbers of Whole Numbers To multiply with mixed numbers or whole numbers, first write any mixed or whole numbers as fractions and then multiply as usual.

Martin-Gay, Developmental Mathematics, 2e 77 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Examples Multiply. a. b.

Martin-Gay, Developmental Mathematics, 2e 88 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Example Multiply.

Martin-Gay, Developmental Mathematics, 2e 99 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Example Multiply. Check by estimating. Let’s check by estimating. rounds to 2, rounds to 1, and 2 · 1 = 2. The estimate is close to the exact value, so our answer is reasonable.

Martin-Gay, Developmental Mathematics, 2e 10 Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall. Example An estimate for the measure of an adult’s wrist is of the waist size. If Jorge has a 34-inch waist, estimate the size of his wrist. Jorge’s wrist is about inches.