Last week, ethan finished 3 1⁄5 books, but this week he only finished 1 4⁄5 books. how many more books did he read last week?

Well first you need to convert the mixed numbers into improper fractions like so

3 1/5 would be 16/5 because 3 times 5= 15+1=16
the same with 1 4/5  but you can do this one a bit differently like so- 1=5/5 + 4/5 = 9/5
So now we move on to the subtraction part of the problem. 16/5-9/5= 7/5 because we know 16-9=7
But now you got to convert this improper fraction back into a proper fraction: 7/ 1 2/5 because 5 goes into 7 one time with a remainder of 2 (2/5)
So the answer would be: Ethan read 1 2/5 more books than he did this week.