There are 3 signs associated with a fraction: => the sign of the numerator => the sign of the denominator => the sign of the whole fraction; (if the fraction were in parentheses, this sign would be written outside).
-- You can change any 2 of them without changing the value of the fraction.
-- Changing any 1 of them changes the effective sign. ___________________________________
Now, you said the fraction is negative. So, let's start with the positive fraction, and see the different ways that we could make it a negative fraction:
=> mark only the numerator negative => mark only the denominator negative => put parentheses around the fraction, and mark it negative outside
If you do any one of these things to a normal positive fraction, it turns into a negative fraction.
Look at the choices you listed in the question:
-- in the numerator only ? Yes. That makes it a negative fraction.
-- in the denominator only ? Yes. That makes it a negative fraction.
-- both ? No. That makes it the same as a positive fraction.
-- put parentheses around the fraction, and a negative sign outside ? Yes. This makes it a negative fraction.
-- it doesn't matter ? No. I hope you can see that it does matter.
Have I confused you ? Is this more than you wanted to know ?
