4/5 os the fourth multiple of what unit fraction?

So, the unit fraction would be 1/5. Keep going from there to 2/5, 3/5, 4/5. So 4/5 was the fourth multiple, However, the answer would have to be a unit fraction and a factor of 4/5, so it has to be 1/5. Equation: 1/5 x 4 = 4/5

I do believe it is the 4th multiple of 1/5 because the unit fraction is 1/5, so if you multiple 1/5 times 4, i believe you get 4/5.