What you would do is change all the fractions to 20ths so they have a common denominator. For 1/5, you multiply 4x5 to get 20 in the denominator. Whatever you multiply on the bottom, you must do at the top. Do that for all fractions and you would get this:
4/20 + 5/20 + 8/20= 17/20 because denominator stays the same, add the values in the numerator.
ANSWER: 17/20