Adding and subtracting fractions

1. Adding and Subtracting
Fractions

2. You may like to take some notes!

3. Adding and subtracting fractions.....a little trickier
than multiplying and dividing3
1

4
3

4. The firstthing you must do is make the
bottomnumbers the same3
1

4
3

5. To make them the same you need to think of the
lowest number that they will both divide into and
the quickest way to do this may be to multiply the
two bottom numbers together3
1

4
3

6. in this example we would do 4 x 3 = 123
1

4
3

7. 12

12 3
1

4
3 =

8. then you need to multiply the top number in each
fraction by the same number that you multiplied
the bottom number by12

12 3
1

4
3
=

9. in the first fraction the 4was multiplied by 3to
turn it into 12so the 3must be multiplied by 3
as well3
1

4
3 12

12
=

10. so now we have3
1

4
3 12

12
9
=

11. and in the second fraction the 3was multiplied
by4to turn it into 12so the 1must be
multiplied by 4as well3
1

4
3 12

12
9
=

12. so now we have3
1

4
3 12
4

12
9
=

13. now we need to add the top numbers together
and leave the bottom numbers alone3
1

4
3 12
4

12
9
=

14. now we need to add the top numbers together
and leave the bottom numbers alone3
1

4
3 12
4

12
9
= =
12
13

15. We have ended up with a “top heavy” fraction.
Divide the bottom number into the top to get a
final answer of 12
4

12
9
=
12
13

16. We have ended up with a “top heavy” fraction.
Divide the bottom number into the top to get a
final answer of 12
4

12
9
=12
1
1
12
13

17. Subtracting fractions
You use exactly the same method as for adding but
at the end you subtract the top numbers from each
other rather than add them