1. Example 3 Multiplying Mixed Numbers POSTCARDS A designer creates postcards that are inches long and inches wide. Find the area of the postcard. 2 1 5 4 3 3 Write area formula. SOLUTION Area Length Width = Substitute values. = 2 1 5 4 3 3 2 11 Write as improper fractions. = 4 15

2. Example 3 Multiplying Mixed Numbers Use rule for multiplying fractions. = 42 15 11 Write as a mixed number. = 8 5 20 The area of a postcard is square inches. ANSWER 8 5 20 Multiply. = 8 165

3. You are making costumes for a school play. Each costume requires yards of fabric. Evaluate when x 3 to determine how many yards of fabric you need to make 3 costumes. Example 4 Using an Algebraic Expression = 9 2 2 COSTUMES 9 2 2 SOLUTION Substitute 3 for x. = 9 2 2 x 9 2 2 3 Write as improper fractions. 9 20 = 1 3 x

4. Example 4 Using an Algebraic Expression Use rule for multiplying fractions. = 19 3 20 Divide out common factors. = 1 20 1313 9393 Multiply. = 3 20 Write as a mixed number. = 3 2 6

5. Example 4 Using an Algebraic Expression ANSWER You need yards of fabric to make 3 costumes. 3 2 6

6. Example 5 Evaluating an Algebraic Expression Evaluate x 2 y Use rule for multiplying fractions. = () 7 –– () 7 – 3 3 34 Write as a factor 2 times. = – 3 7 4 3 – 3 7 – 3 7 x 2yx 2y = 3 1 2 – 4 3 Substitute for x and for y. 3 1 2 – 4 3 2 Write as an improper fraction. = = – 3 7 4 3 3 1 2 – 2 = 4 3 and y. = 3 1 2 – when x

7. Example 5 Evaluating an Algebraic Expression Divide out common factors. = () 7 –– () 7 – 3131 4 1313 3 Multiply. = 12 49 Write as a mixed number. = 12 1 4

8. Guided Practice Find the product. Simplify if possible. for Examples 3, 4, and 5 5. 5 2 1 2 1 3 ANSWER 10 9 4 6. 2 1 5 6 5 1 – ANSWER 12 1 10 – ANSWER 20 19 14 – 7. 5 3 2 4 3 5 – 8. 3 1 2 – – 4 3 ANSWER 4 3 1

9. Guided Practice 9. WHAT IF? for Examples 3, 4, and 5 In Example 4, how many yards of fabric would be needed to make 5 costumes? ANSWER 9 1 11 yd Evaluate the expression when x and y. = 6 5 1 – 4 3 = 10. x 3 2 ANSWER – 2 1 11. 2y ANSWER 3 2 3

10. Guided Practice for Examples 3, 4, and 5 Evaluate the expression when x and y. = 6 5 1 – 4 3 = 12. xy 13. xy 2 ANSWER 8 3 1 – 48 25 2 –