<span>A unit fraction is a fraction where the denominator is one, so the easiest way to write 4/5 as a sum of unit fractions is to use 1/5. So the answer would be 1/5+1/5+1/5+1/5. Add up all the numerators and put that over their like denominators to get 4/5!</span><span />
C because the most common factor would be 15 cus 15 goes into 15 once, 30 twice, and 60 four times which is an easy way of figuring out the the greatest common factor and I hope that helped :-)