Though comparing fractions can be confusing enough, bringing negative signs into the mix doesn't have to add to that confusion. Fractions are actually two stacked integers, with the one above the line called the numerator and the one beneath it the denominator. Numbers are negative  and signified with a minus sign, or ""  when they are less than zero. Negative numbers work in reverse because as numbers increase their values lessen. You can compare the values of negative fractions with like and unlike denominators through the numbers appearing in the fractions.
Same Denominator

Find two negative fractions with like denominators for example purposes. For this example, let the fractions be 2/9 and 7/9.

Separate the numerators from the fractions. In this example, the numerators are 2 and 7.

Compare the numerators. The numerator that is greater in value indicates the greater fraction. Concluding this example, when comparing 2 and 7, 2 is greater than 7, so 2/9 is greater than 7/9.
Different Denominators

Find two negative fractions with different denominators for example purposes. With this example, let the fractions be 3/4 and 7/8.

Multiply each fractions' numerators by the others' denominators, assigning each fraction's negative sign to its numerator. In this example, multiplying 8 and 3 equals 24, and multiplying 7 and 4 equals 28.

Compare the two products from the previous step. If the product that includes the first fraction's numerator is greater than the other product, the first fraction is greater in value; if the product is less than the second one, the fraction is less in value; and if they are equal, the fractions are equivalent. Concluding this example, 24 is greater than 28; the fraction 3/4 is therefore greater than 7/8.