Fractions A quick help for those who have forgotten how to work with them.

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



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 with like denominators. When you have like denominators, you subtract the numerators, then reduce.


8

3

8

1Example 1


4

1

8

2

Example 1


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


Example 2

7

2

3

2

7

2

3

27

7

3


Example 2

3

21

6

21

14


Example 2

21

8


Example 2


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.


Example 3

4

33

3

21


4

15

3

5Example 3

4

15

3

544

3


Example 3

3

12

45

12

20


Example 3

4

5

12

15


Example 3

4

11

4

5


Example 3


Try these:

4

1

8

3. 1

9

2

12

5. 2

6

15

4

13. 3


Answers:

8

1. 1

36

7. 2

12

111. 3

Fraction Operations



Multiplying Fractions


When multiplying fractions we don’t care about having common denominators. We just multiply straight across.


8

3

8

1Example 1


64

3Example 1


Example 2

7

2

3

1

21

2


Example 2


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.


Example 3

4

33

3

21


4

15

3

5Example 3

4

15

3

5


Example 3

4

25

12

75


Example 3

4

16

4

25


Example 3


Try these:

4

1

8

3. 1

9

2

12

5. 2

6

15

4

13. 3


Answers:

32

3. 1

54

5. 2

24

1916. 3

Fraction Operations



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



The End

Fractions A quick help for those who have forgotten how to work with them.

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