Learn how to add and subtract mixed numbers.

1. 6.4 Adding and
Subtracting Mixed
Numbers

2. Adding Mixed Numbers
Find the sum.
1. Rewrite the fraction using
4
1 LCD if denominators are
9 different.
1 2. Add or subtract the
+ 3 fractions,
9 then the whole numbers.
3. Simplify if possible.
5
4
9 In this problem, the denominators are the
same, so begin with step 2.

3. Let’s Do More Examples!
Find the sum.
4 7
1 4
9 8
X2
1 X3
3 1 2
3 5 =
+ = +
3 9 4 8
X3 X2
9 1
7
4 9 = 1
8 8
9
1
10 Add the whole numbers.
8

4. Subtracting Mixed
Numbers
Find the Difference.
X6
3
= 18 10 7
1 17 3
4 X 6 24 8
20
1 X4 1
3 X 4 12 4
= = 4
- 1 - 1 6 24 - 8
5 X 4 20 X4
6
5 = 3
= 1 14 7 6
2 =
8 4
20 4 24 12
3
7 6
2 4
12

5. Now You Try!
Find the sum or difference.
3 X2 6 5 10
3 = 4 =
5 X 2 10 6 12
9 1
+ 7 10 - 1 12
15 5 1 9 = 3
10 = 1 = 3
10 10 2 12 4
1
11 3
2 3
4

6. Now You Try!
Find the sum or difference.
3 X2 6 5 10
3 = 4 =
5 X 2 10 6 12
9 1
+ 7 10 - 1 12
15 5 1 9 = 3
10 = 1 = 3
10 10 2 12 4
1
11 3
2 3
4