Warm Up
Write each number as an improper fraction.
1.
1
3
2
7
3
2.
7
8
1
15
8
3.
2
5
3
17
5
4.
2
3
6
20
3
5.
3
8
5
43
8
Problem of the Day
The sum of three consecutive integers is168. What are the three integers?
55, 56, and 57
Notice that multiplying a fraction by a wholenumber is the same as multiplying the wholenumber by just the numerator of the fractionand keeping the same denominator.
14
34
14
+
+
=
Repeated addition
14
3
3
4
=
=
Multiplication
3 • 1
4
1
4
–8
67
Multiply. Write the answer in simplest form.
Multiply.
Simplify.
–48
7
–6
67
–8 • 6
7
To write as a mixednumber, divide:
Helpful Hint
–487
–48
7
= –6 R6
67
= –6
Additional Example 1A: Multiplying a Fraction and anInteger
2
13
Multiply.
Simplify.
10
23
163
2
323
5
5(3) + 13
=
=
13
5
163
Multiply. Write the answer in simplest form.
Additional Example 1B: Multiplying a Fraction and anInteger
–3
58
Multiply. Write the answer in simplest form.
Multiply.
Simplify.
–158
–1
78
–3 • 58
Check It Out: Example 1A
4
25
Multiply.
Simplify.
37
35
475
4
1885
9
9(5) + 25
=
=
25
9
475
Check It Out: Example 1B
Multiply. Write the answer in simplest form.
A fraction is in lowest terms, or simplest form,when the numerator and denominator haveno common factors.
Caution!
1(6)8(7)
Multiply. Write the answer in simplest form.
67
Simplify.
328
18
1(6)8(7)
Multiply numerators.
Multiply denominators.
Look for common factors: 2.
3
4
Additional Example 2A: Multiplying Fractions
–2(9)3(2)
–2(9)3(2)
3
1
Simplify.
–3
Multiply numerators.
Multiply denominators.
Look for common factors: 2, 3.
92
23
–
1
–1
Additional Example 2B: Multiplying Fractions
Multiply. Write the answer in simplest form.
3(5)5(8)
Multiply. Write the answer in simplest form.
58
Simplify.
38
35
3(5)5(8)
Multiply numerators.
Multiply denominators.
Look for common factors: 5.
1
1
Check It Out: Example 2A
–7(4)8(7)
–7(4)8(7)
1
2
Simplify.
Multiply numerators.
Multiply denominators.
Look for common factors: 4, 7.
47
78
–
1
–1
12
–
Multiply. Write the answer in simplest form.
Check It Out: Example 2B
Multiply.
Product is negativewith 2 decimal places.
2 • (–0.51) = –1.02
B. (–0.4)(–3.75)
Product ispositive with 3decimal places.
(–0.4) • (–3.75) = 1.500
You can drop the zeros after the decimal point.
= 1.5
Additional Example 3: Multiplying Decimals
A. 2(–0.51)
00
3.1 (0.28)
Multiply.
Product is positivewith 3 decimal places.
3.1 • (0.28) = 0.868
(–0.4)(–2.53)
Product is positivewith 3 decimal places.
(–0.4) • (–2.53) = 1.012
Check It Out: Example 3
A.
B.
Joy completes of her painting each day.
How much of her painting does she completein a 7 day week?
Write as an improper fraction.
120
Additional Example 4: Application
=
(7) =
120
Multiply.
120
71
1 • 720 • 1
=
720
Joy completes of her painting in a 7-day week.
720
Mark runs mile each day. What is the total
distance Mark runs in a 5-day week?
Write as an improper fraction.
17
Check It Out: Example 4
=
(5) =
17
Multiply.
17
51
1 • 5I7 • 1
=
57
Mark runs mile in a 7-day week.
57
4. Evaluate 2 (x) for x = .
1.
Lesson Quiz
Multiply.
–1.034
2.
58
23
–
17
9
3. –0.47(2.2)
12
2
45
–
512
1
27
Edgar runs mile each day. What is the totaldistance that Edgar runs in a 7-day week?
5.
89
6 miles
29
1. Multiply.
8
A. 1C. 2
B. 1D. 8
Lesson Quiz for Student Response Systems
25
35
45
15
15
2. Multiply.
–
A. –C. –
B. –D. –
Lesson Quiz for Student Response Systems
712
512
718
518
79
34
3. Multiply.
–0.39(3.2)
A. –1.238
B. –1.248
C. –1.428
D. –1.842
Lesson Quiz for Student Response Systems