How do you add and subtract fractions with the same denominator?

An example would be

8/12 - 4/12 = 4/12

8/12 + 4/12 = 12/12 = 1

Another example would be

13/24 - 9/24 = 4/24 = 1/6

13/24 + 9/24 = 22/24 = 11/12

Lastly, another example is:

4/6 - 3/6 = 1/6

4/6 + 3/6 = 7/6 = 1 1/6