To subtract a fraction in negative, you must first change the fraction to a positive. To do this, multiply the numerator and denominator by -1. Once you have changed the fraction to a positive, you can then subtract it from the other fraction as usual.
For example, to subtract the fraction -1/2 from the fraction 1/3, you would first change the fraction -1/2 to a positive by multiplying the numerator and denominator by -1. This would give you the fraction 1/2. You can then subtract this fraction from the fraction 1/3 as usual, which would give you the answer 1/6.
