Slide 13-9
Warm Up
1. 24 2. 16
3. 30 4. 28
Problem of the Day
At midnight Caitlin heard a forecaster say that it would be cloudy for exactly 72 hours and then would be sunny. Caitlin knew the forecaster was wrong. Explain.
*
Learn to multiply fractions and mixed numbers.
3-9
numerators to find the product’s
numerator. Then multiply the
denominator.
3-9
Multiply. Write the answer in simplest form.
Additional Example 1A: Multiplying Fractions
–12 ·
3
4
–12 ·
3
4
=
–
Multiply numerators.
Multiply denominators.
The product of two positive proper fractions is less than either fraction.
Helpful Hint
Multiply. Write the answer in simplest form.
Additional Example 1B: Multiplying Fractions
·
Multiply. Write the answer in simplest form.
Additional Example 1C: Multiplying Fractions
·
The signs are different, so the answer will be negative.
Multiply numerators.
Multiply denominators.
Multiply. Write the answer in simplest form.
Check It Out: Example 1A
–16 ·
1
4
–16 ·
1
4
=
–
Multiply. Write the answer in simplest form.
Check It Out: Example 1B
·
Multiply. Write the answer in simplest form.
Check It Out: Example 1C
·
The signs are different, so the answer will be negative.
Multiply numerators.
Multiply denominators.
Multiply. Write the answer in simplest form.
Additional Example 2A: Multiplying Mixed Numbers
Write the mixed number as an
improper fraction.
Multiply. Write the answer in simplest form.
Additional Example 2B: Multiplying Mixed Numbers
Write the mixed numbers as improper fractions.
Simplify.
4
1
5
Multiply. Write the answer in simplest form.
Additional Example 2C: Multiplying Mixed Numbers
Multiply numerators.
Multiply denominators.
Simplify.
3
Multiply. Write the answer in simplest form.
Check It Out: Example 2A
Write the mixed number as an
improper fraction.
Multiply. Write the answer in simplest form.
Check It Out: Example 2B
Write the mixed numbers as improper fractions.
Simplify.
3
3
6
Multiply. Write the answer in simplest form.
Multiply numerators.
Multiply denominators.
Simplify.
9
Multiplying Fractions and Mixed Numbers
In 2001, the car toll on the George Washington Bridge was $6.00. In 1995 the toll was
Additional Example 3: Transportation Application
2
3
+
Simplify.
= $4.00
Divide 4 by 1 to write the fraction as a decimal.
+
+
+
+
Multiplying Fractions and Mixed Numbers
In 2002, the fee to park in a parking garage was
$4. In 2000 the fee was of the fee in 2002.
What was the fee in 2000?
Check It Out: Example 3
Simplify.
= $3.00
Divide 3 by 1 to write the fraction as a decimal.
The fee to park in the parking garage was $3.00 in 2000.
3
4
3
4
4 ·
Standard Lesson Quiz
3-9
Lesson Quiz: Part I
1.
1
8
Lesson Quiz: Part II
5.
1
4
much butter do you need?
1
1
8
pounds
1. Multiply. Write your answer in simplest form.
·
4 45
1 6
1 9
1 10
1 9
4 5
2. Multiply. Write your answer in simplest form.
4 ·
B. or 3 D.
17 3
16 5
8 5
4 5
4 5
1 3
2 3
1 5
3 5
3. Multiply. Write your answer in simplest form.
6 · 1
35 4
27 4
26 5
24 4
1 4
2 5
3 4
3 4
1 5
4 5
4. Multiply. Write your answer in simplest form.
· 3
8 9
17 18
19 18
1 9
5 18
4 5
1 18
5. To prepare one bowl of salad, 3 pounds
of vegetables are required. How many pounds of vegetables are required to prepare one-third bowl of salad?
A. 1 lb C. 1 lb
B. 1 lb D. 1 lb
Lesson Quiz for Student Response Systems
1 4
1 2
3 4
3 5
3 4