So lets just forget about the whole #'s right now (don't worry, we will get back to that)

1 1

--- - ---

4 3

You have to find a common denominator.

What 3's can 4 and 3 make?

assuming you want the smallest one, it will be 12

You have to times the bottom by a number to make them 12, but what you do to the bottom, you must do to the top.

1*3 1*4

--- - ---

4*3 3*4

That makes:

3 4

--- - ---

12 12

Now that you have common denominators, you can treat this like a normal subtraction. (You cannot subtract the denominators though, or else what was the point of finding a common denominator?)

3 4 1

--- - --- = - ---

12 12 12

Now time to take your whole numbers:

3-2=1

Now since you have a negative number, you have to add that whole number you have.

1 12

- --- + ----

12 12

All you would have to do is minus one from the 12 from the top of the second fraction because of your negative, and your answer would be 11/12

Hope that wasn;t to complex, probably confused ytou more.