First you must compare the denominators
(bottom number) and I usually multiply up if it's a 2,5,10,20,30,40,50,60..... since both numbers are a factor of 100 it's easier. Think about it like change there are 20 nickels in $1.00 and $1.00= 100 pennies. So you have to multiply 5•20 and you get 100 then the rule of fractions what is done to the bottom must be done to the top. Which means that you have to multiply 2•20 and you get 40 finally the easy part the comparing.
40/100 and 35/100
40 is greater so the you use the greater than sign so the answer could be any of the following:
2/5>35/100
40/100>35/100
Or
2/5>7/20