This document provides instructions for adding, subtracting, multiplying, and dividing fractions. It explains that to add or subtract fractions, the denominators must be the same. It shows how to change fractions to equivalent fractions with a common denominator to allow addition or subtraction. It also explains how to multiply and divide fractions by multiplying or dividing the numerators and denominators. Examples are provided to demonstrate each process.

1. 



This presentation will help you to:
add
subtract
multiply and
divide fractions

2. To add fractions together the denominator
(the bottom bit) must be the same.
Example
1 2
+ =
8 8

3. To add fractions together the denominator
(the bottom bit) must be the same.
Example
1 2 1+ 2
+ =
=
8
8 8

4. To add fractions together the denominator
(the bottom bit) must be the same.
Example
1 2 1+ 2 3
+ =
=
8
8 8
8

5. Click to see the next slide to reveal the answers.
1 1
+ =
3 3
2 1
+ =
2.
4 4
2 4
+ =
3.
7 7
3 7
4. + =
12 12
1.

6. 1.
2
1 1
+ =
3
3 3
3. 2 4
6
+ =
7
7 7
2. 2 1
3
+ =
4 4 4
4. 3
7 10
+ =
12 12 12

7. Subtracting fractions
To subtract fractions the denominator (the bottom
bit) must be the same.
Example
3 2
− =
8 8

8. Subtracting fractions
To subtract fractions the denominator (the bottom
bit) must be the same.
Example
3 2 3− 2
− =
=
8
8 8

9. Subtracting fractions
To subtract fractions the denominator (the bottom
bit) must be the same.
Example
3 2 3− 2 1
− =
=
8
8 8
8

10. Now try these
Click on the next slide to reveal the answers.
1.
3.
2 1
− =
3 3
4 3
− =
7 7
2.
4.
2 1
− =
4 4
7 3
− =
12 12

11. Now try these
.
1.
3.
2 1 1
− =
3 3 3
4 3 1
− =
7 7 7
2.
4.
2 1 1
− =
4 4 4
7 3 4
− =
12 12 12

12. Multiplying fractions
To multiply fractions we multiply
the tops and multiply the bottoms
Top x Top
Bottom x Bottom

13. Multiplying fractions
Example
1 1
× =
2 3

14. Multiplying fractions
Example
1 1 1× 1
=
× =
2 3 2×3

15. Multiplying fractions
Example
1 1 1× 1
1
=
× =
2 3 2×3
6

16. Now try these
Click on the next slide to reveal the answers.
1.
3.
1 1
× =
3 3
2 4
× =
4 5
2.
4.
2 1
× =
4 4
1 3
× =
3 5

17. Now try these
.
1.
3.
1 1 1
× =
3 3 9
2 4 8
× =
4 5 20
2.
4.
2 1 2
× =
4 4 16
1 3 3
× =
3 5 15

18. Dividing fractions
Once you know a simple trick,
dividing is as easy as multiplying!
• Turn the second fraction upside down
• Change the divide to multiply
• Then multiply!

19. Dividing fractions
Example
1 1
÷ =?
6 3
•Turn the second fraction upside down
1 3
÷
6 1

20. Dividing fractions
Example
1 1
÷ =?
6 3
•Turn the second fraction upside down
1 3
÷
6 1
•Change the divide into a multiply
1 3
×
6 1

21. Dividing fractions
Example
1 1
÷ =?
6 3
•Turn the second fraction upside down
1 3
÷
6 1
•Change the divide into a multiply
1 3
×
6 1
•Then multiply
1 3 1× 3
× =
=
6 1 6 ×1

22. Dividing fractions
Example
1 1
÷ =?
6 3
•Turn the second fraction upside down
1 3
÷
6 1
•Change the divide into a multiply
1 3
×
6 1
•Then multiply
1 3 1× 3
3
× =
=
6 1 6 ×1
6

23. Now try these
Click on the next screen to reveal the answers.
1.
3.
1 1
÷ =
3 2
1 2
÷ =
4 6
2.
4.
1 2
÷ =
4 3
1 4
÷ =
2 5

24. Now try these
1.
3.
1 1 2
÷ =
3 2 3
1 2 6
÷ =
4 6 8
2.
4.
1 2 3
÷ =
4 3 8
1 4 5
÷ =
2 5 8

25. To add or subtract fractions together the
denominator (the bottom bit) must be the
same.
So, sometimes we have to change the
bottoms to make them the same.
In “maths-speak” we say we must get
common denominators

26. To get a common denominator we have to:
1. Multiply the bottoms together.
2. Then multiply the top bit by the correct
number to get an equivalent fraction

27. For example
1 1
− =?
2 3

28. For example
1 1
− =?
2 3
1. Multiply the bottoms together
2×3 = 6

29. For example
1 1
− =?
2 3
2. Write the two fractions as sixths
1 ?
=
2 6
1 ?
=
3 6

30. For example
1 1
− =?
2 3
To get ½ into sixths we have multiplied
the bottom (2) by 3. To get an
equivalent fraction we need to multiply
the top by 3 also

31. For example
1 1
− =?
2 3
To get ½ into sixths we have multiplied
the bottom (2) by 3. To get an
equivalent fraction we need to multiply
the top by 3 also
1 1× 3 3
=
=
2
6
6

32. For example
1 1
− =?
2 3
To get 1/3 into sixths we have multiplied
the bottom (3) by 2. To get an
equivalent fraction we need to multiply
the top by 2 also

33. For example
1 1
− =?
2 3
To get 1/3 into sixths we have multiplied
the bottom (3) by 2. To get an
equivalent fraction we need to multiply
the top by 2 also
1 1× 2 2
=
=
3
6
6

34. For example
1 1
− =?
2 3
We can now rewrite
1 1
− =
2 3

35. For example
1 1
− =?
2 3
We can now rewrite
1 1 3 2
− = −
2 3 6 6

36. For example
1 1
− =?
2 3
We can now rewrite
1 1 3 2 3− 2
− = − =
6
2 3 6 6

37. For example
1 1
− =?
2 3
We can now rewrite
1 1 3 2 3− 2
− = − =
6
2 3 6 6
1
=
6

38. This is what we have done:
1 1
? ?
− = −
2 3 6 6
1. Multiply the
bottoms

39. This is what we have done:
1 1
? ? 1× 3 ?
− = − =
−
2 3 6 6
6
6
1. Multiply the
bottoms
2.Cross
multiply

40. This is what we have done:
1 1
? ? 1× 3 ? 3 1× 2
− = − =
− = −
2 3 6 6
6
6
6 6
1. Multiply the
bottoms
2.Cross
multiply

41. This is what we have done:
1 1
? ? 1× 3 ? 3 1× 2
3 2
− = − =
= −
− = −
2 3 6 6
6
6 6
6
6 6
1. Multiply the
bottoms
2.Cross
multiply

42. Now try these
Click on the next slide to reveal the answers.
1.
3.
1 1
+ =
3 2
3 1 14
− =
4 6 24
2.
4.
1 2
+ =
4 3
4 1
+ =
5 2

43. Now try these
1.
3.
5
1 1
+ =
6
3 2
3 1 14 7
− = =
4 6 24 12
2.
4.
1 2 11
+ =
4 3 12
3
4 1
+ =
5 2
10

44. Go to:
 BBC Bitesize Maths Revision site
by clicking here: