If the fraction is similar just add the numerator and copy the denominator . when the fraction is dissimilar find the LCD  then divide it to the denominator then the answer there add to the numerator.,, like this L: 1/2 + 1/3 the LCD is 6 , so 6 divided by 2 is 3 multiply by 1 ,,,, that's all you gotta do ,, if the fraction is improper just divide the numerator by the denominator then the quotient will be the whole number then the remainder(if the answer have ) that would be the numerator but if it don't , the quotient would be then the denominator that you used to divide by the numerator would be the same denominator again ...