The decimal form of 80% is .80 meaning you have 80 parts of 100 so the fraction would be expressed as 80/100. Then this fraction can be further reduced, first I would devide both the numerator and denominator by ten so you are left with 8/10 which can be further reduced. So I would devide bothe the Num. and dem. by 2 and would end up with 4/5.