You have to divide the numerator by the denominator if it's an improper fraction, but, if it is a mixed which is A b/c, then you multiply A with c, then you add the numerator which is b to the product and write the denominator as it is. After that, divide the numerator by the denominator.
Example:
Improper: 3/4 = 3 divided by 4 = 0.75
Mixed: 3 3/4 = 3*4+3= 15/4 = 3.75