FractionsA quick help for those who have forgotten how to work with them.
Fraction Operations
• Addition• Subtraction• Multiplicatio
n• Division• Exit
Adding Fractions
Adding Fractions
In order to add fractions you must have common denominators and for the sake of this presentation you must also change all mixed numbers to improper fractions.
Adding Fractions
Adding fractions with like denominators. When you have like denominators, you add the numerators, then reduce.
Adding Fractions
8
3
8
1Example 1
Adding Fractions
2
1
8
4
Example 1
Adding Fractions
When fractions have uncommon denominators multiply the denominators together, then multiply the numerator by the same number you multiplied the denominator by. This will always give you a common denominator.
Adding Fractions
Example 2
7
2
3
1
7
2
3
17
7
3
Adding Fractions
Example 2
3
21
6
21
7
Adding Fractions
Example 2
21
13
Adding Fractions
Example 2
Adding Fractions
When you have mixed numbers change the mixed number to an improper fraction then add as before. However, if you start out with a mixed number you need to convert your answer to a mixed number as well.
Adding Fractions
Example 3
4
33
3
21
Adding Fractions
Example 3
4
15
3
5
4
15
3
544
3
Adding Fractions
Example 3
3
12
45
12
20
Adding Fractions
Example 3
12
55
12
65
Adding Fractions
Example 3
Adding Fractions
Try these:
4
1
8
3. 1
9
2
12
5. 2
6
15
4
13. 3
Adding Fractions
Answers:
8
5. 1
36
23. 2
12
58. 3
Fraction Operations
• Addition• Subtraction• Multiplicatio
n• Division• Exit
Subtracting Fractions
Subtracting Fractions
In order to subtract fractions you must have common denominators and for the sake of this presentation you must also change all mixed numbers to improper fractions.
Subtracting Fractions
Subtracting fractions with like denominators. When you have like denominators, you subtract the numerators, then reduce.
Subtracting Fractions
8
3
8
1Example 1
Subtracting Fractions
4
1
8
2
Example 1
Subtracting Fractions
When fractions have uncommon denominators multiply the denominators together, then multiply the numerator by the same number you multiplied the denominator by. This will always give you a common denominator
Subtracting Fractions
Example 2
7
2
3
2
7
2
3
27
7
3
Subtracting Fractions
Example 2
3
21
6
21
14
Subtracting Fractions
Example 2
21
8
Subtracting Fractions
Example 2
Subtracting Fractions
When you have mixed numbers change the mixed number to an improper fraction then subtract as before. However, if you start out with a mixed number you need to convert your answer to a mixed number as well.
Subtracting Fractions
Example 3
4
33
3
21
Subtracting Fractions
4
15
3
5Example 3
4
15
3
544
3
Subtracting Fractions
Example 3
3
12
45
12
20
Subtracting Fractions
Example 3
4
5
12
15
Subtracting Fractions
Example 3
4
11
4
5
Subtracting Fractions
Example 3
Subtracting Fractions
Try these:
4
1
8
3. 1
9
2
12
5. 2
6
15
4
13. 3
Subtracting Fractions
Answers:
8
1. 1
36
7. 2
12
111. 3
Fraction Operations
• Addition• Subtraction• Multiplicatio
n• Division• Exit
Multiplying Fractions
Multiplying Fractions
When multiplying fractions we don’t care about having common denominators. We just multiply straight across.
Multiplying Fractions
8
3
8
1Example 1
Multiplying Fractions
64
3Example 1
Multiplying Fractions
Example 2
7
2
3
1
21
2
Multiplying Fractions
Example 2
Multiplying Fractions
When you have mixed numbers change the mixed number to an improper fraction, then multiply as before. However, if you start out with a mixed number you need to convert your answer to a mixed number as well.
Multiplying Fractions
Example 3
4
33
3
21
Multiplying Fractions
4
15
3
5Example 3
4
15
3
5
Multiplying Fractions
Example 3
4
25
12
75
Multiplying Fractions
Example 3
4
16
4
25
Multiplying Fractions
Example 3
Multiplying Fractions
Try these:
4
1
8
3. 1
9
2
12
5. 2
6
15
4
13. 3
Multiplying Fractions
Answers:
32
3. 1
54
5. 2
24
1916. 3
Fraction Operations
• Addition• Subtraction• Multiplicatio
n• Division• Exit
Division
Dividing Fractions
We never really divide fractions. We take the first fraction and multiply it by the reciprocal of the second fraction.
Dividing Fractions
Hint for dividing fractions:
To get the right answer, flip the fraction on the right.
Dividing Fractions
8
3
8
1Example 1
Dividing Fractions
3
8
8
1Example 1
Dividing Fractions
3
1
24
8
Example 1
Dividing Fractions
Example 2
7
2
3
2
Dividing Fractions
Example 2
2
7
3
2
3
7
6
14
Dividing Fractions
Example 2
Dividing Fractions
When you have mixed numbers change the mixed number to an improper fraction, then divide as before. However, if you start out with a mixed number, you need to convert your answer to a mixed number as well.
Dividing Fractions
Example 3
4
33
3
21
Dividing Fractions
4
15
3
5Example 3
Dividing Fractions
15
4
3
5Example 3
9
4
45
20
Dividing Fractions
Example 3
Dividing Fractions
Try these:
4
1
8
3. 1
9
2
12
5. 2
6
15
4
13. 3
Dividing Fractions
Answers:
2
3. 1
8
15. 2
62
39. 3
Fraction Operations
• Addition• Subtraction• Multiplicatio
n• Division• Exit
The End