The numerator of a fraction is that part that is above the division line. In 2/3, 2 is the numerator. In (x-3)/(x+3), the binomial (x-3) is the numerator. In general, a fraction is (numerator)/(denominator). There are many questions that involve finding the value of the numerator. Most have to do with adding or subtracting fractions. In the general case, (a/b) + (c/d) = (ad + bc)/(bd)
For example, (1/2) + (3/5) = (1*5 + 2*3)/(2*5) = (5+6)/10 = 11/10 The numerator of the result is 11. Because it is larger than the denominator, this is called an "improper" fraction. In "mixed number" form, it is equal to 1 1/10. In decimal form, 1.1. The above equation also works when one or both of the denominators is 1. 3 + 4/5 = (3/1 + 4/5) = (3*5 + 1*4)/(1*5) = (3*5 + 4)/5 = 19/5