Please note that 23/20 is a perfectly respectable number. The passion for changing it into 1 3/20 (or, more likely, into something else that is wrong) is a passion whose inspiration eludes me. Whether you should leave a fraction as 23/20 or 1 3/20 depends on what you are going to do with it; one is certainly not more "improper" than the other.
Numbers have no morals.
C.J. De Jager
South African mathematics educator