It would be two fifths turned into tenths which is two tenths - (when you turn fifths into tenths, you multiply it by 2 so you do the same with the numerator.) You do not change the denominator so you subtract the numerators 2-1=1. The answer is one tenth.
As these numbers have the same denominator (5), we can simply take off unit for unit: 5-2 = 3 1/5 - 3/5 = -2/5 So we get 3-2/5 which is 2 and 3/5 So the answer to 5 and one fifth minus 2 and three fifths is 2 and three fifths.
Well, a fifth is one fifth of one, that's why it's called a fifth, it's divided into five. If your question was 'what is a fifth a tenth of?', then the answer would be two. What is a fifth a seventh of? 1.4, etc.