To convert a mixed number to an improper fraction, multiply the denominator by the whole number, add that total to the numerator and put the whole thing over the original denominator.
5 and 4/250
900% = 9⁄1 = 9
Mixed fractions can't become proper fractions. Mixed fractions are greater than one.
-0.92 is 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 rational equivalent is -92/100 which can be simplified, if required.
To convert a mixed number to an improper fraction, multiply the denominator by the whole number, add that total to the numerator and put the whole thing over the original denominator.