It is: 33/138 = 11/46 in its lowest terms
138 is an integer and not really a fraction but it can be expressed as a fraction: in the form 138/1
5.52 = 5 and 52/100 = 5 and 13/25 = 138/25
138 is an integer, not a fraction.
138 is whole number not a fraction there for the mixed is not needed
Any proper fraction is less than 138%. There are an infinite number of them. (There are also an infinite number of improper fractions that are less than 138%, but that's another story.)
138/10 in improper fraction. 13 8/10 in mixed fraction
-0.138 is already a fraction. It is a fraction in decimal form rather than in the form of a ratio. However, that does not stop it being a fraction.Its equivalent, in rational form, is -138/1000 which you can simplify, if you so wish.