Math 64
4.7 "Operations on Mixed Numbers"
Objective:
*
Multiply, divide, add, or subtract mixed numbers.
*
Solve problems containing mixed numbers.
*
Perform operations on negative mixed numbers.
Multiplying or Dividing with Mixed Numbers or Whole Numbers
Multiplying or Dividing with Mixed Numbers or Whole Numbers:
To multiply or divide with mixed numbers or whole numbers, …rst write any mixed or
whole numbers as improper fractions and then multiply or divide as usual.
Example 1: (Multiplying mixed numbers)
Find the following products.
a)
2 13
3 12
b)
2 23 5 41 6
c) 5 35
15
4
Example 2: (Dividing mixed numbers)
Find the indicated quotients, and write your answers in mixed number form.
1
a) 3 10
2 21
b)
3
6 11
3
4
Page: 1
c) 7 15
( 3)
Notes by Bibiana Lopez
Prealgebra by Elayn Martin-Gay
4.7
Adding or Subtracting Mixed Numbers
Adding or Subtracting Mixed Numbers:
kTo add or subtract mixed numbers, add or subtract the fraction parts and then add or subtract the whole number parts.k
Example 3: (Adding mixed numbers)
Find each sum.
18
a) 5 12 + 3 15
b)
1
c) 3 57 + 1 14
+ 4 53
3
d) 5 43 + 9 10
+2
+
1 54
Example 4: (Subtracting mixed numbers)
Find each di¤ erence.
a) 11 12
4 72
9
b) 6 10
Page: 2
3 35
Notes by Bibiana Lopez
Prealgebra by Elayn Martin-Gay
3
19 10
c)
4.7
d) 18 37
8 12
15 23
Solving Problems Containing Mixed Numbers
Example 5: (Applications)
The Saltalamachios are planning to build a deck that measures 4 12 yards by 6 13 yards. Find the area of their proposed deck.
Example 6: (Applications)
A homeowner has 15 23 feet of plastic pipe. She cuts o¤ a 2 21 foot length and then a 3 14 foot length. If she now needs a 10-foot
piece of pipe, will the remaining piece do? If not, by how much will the piece be short?
Operating on Negative Mixed Numbers
Example 7: (Operating on negative mixed numbers)
Perform the indicated operations.
a)
20 25
3
30 10
b)
Page: 3
4 41
2 38
Notes by Bibiana Lopez