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: