3. What are we really doing? What multiplication problem goes with this model?
4. Put your answer in simplest form! Remember! To multiply fractions, first multiply the numerator, then multiply the denominator.
5.
6. • = 1 • 2 4 • 5 = = Multiply numerators. Multiply denominators. The GCF of 2 and 20 is 2. The answer is in simplest form. 1 4 __ 2 5 __ 2 20 __ 1 10 __
7. • _____ = = Use the GCF to simplify the fractions before multiplying. The greatest common factor of 5 and 15 is 5. 1 • 4 7 • 3 • Multiply numerators. Multiply denominators. The answer is in simplest form. • 1 3 = Simplify first- Another method 5 7 __ 4 15 __ 4 21 __ 5 7 __ 4 15 __ 1 7 __ 4 3 __
8. • ______ = = Multiply numerators. Multiply denominators. 4 • 6 9 • 10 • The GCF of 24 and 90 is 6. The answer is in simplest form. = 4 9 __ 6 10 __ 24 90 __ 4 9 __ 6 10 __ 4 15 __
9. Multiply. Write each answer in simplest form. 1. 2. Evaluate the expression x • for each value of x . Write the answer in simplest form. 3. x = 4. x = 5. At a particular college of the students take a math class. Of these students, take basic algebra. What fraction of all students take basic algebra? • • 3 5 __ 1 4 __ 5 7 __ 3 10 __ 1 8 __ 4 5 __ 1 8 __ 2 5 __ 1 4 __ 3 20 __ 3 14 __ 1 10 __ 1 64 __ 1 10 __
10. Reciprocals can help you divide by fractions. Two numbers are reciprocals if their product is 1.
11. RECIPROCALIOUS! Find the reciprocal. of is 1. The reciprocal of is 9. 1 9 __ 1 9 __ • = 1 Think: of what number is 1? 1 9 __ 1 9 __ 1 9 __ • 9 = 1 1 9 __ 9 1 __ 1 9 __
12. ÷ ÷ = • Rewrite as multiplication using the reciprocal of , . Simplify before multiplying. = You can write the answer as a mixed number. = 1 2 Multiply. = 3 7 10 __ 7 10 __ 5 1 __ 7 10 __ 5 1 __ 7 • 5 10 • 1 ____ 7 2 __ 1 5 __ 1 5 __ 1 5 __ 1 2 __
13. ÷ 3 ÷ 3 = • Multiply by the reciprocal. = The answer is in simplest form. = 2 3 __ 2 3 __ Rewrite as multiplication using the reciprocal of 3, . 1 3 __ 2 3 __ 1 3 __ 2 • 1 3 • 3 ____ 2 9 __
