The answer is: True.
The numerator of a fraction is the number that is written in the upper part of it and the denominator is the number that is written in the lower part.
To substract fractions, they must have a common denominator. There is two cases:
1. When the fractions have the same denominator, you just have to rewrite the denominator and substract the numerators. For example:
8/3-1/3=(8-1)/3=7/3
2. When the fractions have different denominators, you must calculate the Least commom multiple (LCM):
5/2-3/4
L.C.M.=2²=4
(10-3)/4=7/4