Fractions: rules for adding neg & pos fractions 1/125-1/250 = this confuses me?

The rule is: Before you can add or subtract fractions, they must have

the same denominator.

For this little problem, don't worry about the signs yet. Just make both

fractions have the same denominator. I suggest you change the first one

to something over 250.

When your fractions have the same denominator, you get the sum or difference

like this:

- - The numerator of the answer is the sum or difference of the two numerators.

- - The denominator of the answer is the same as the denominator of the two fractions.