Note that the whole number 1 = 20/20
As 20/20 = 1
There are 4 whole numbers. multiply the numerator by 4
(20/20) x (4/1) = 80/20
Next, add the improper fraction gotten to the fraction given, 12/20
80/20 + 12/20 = 92/20
92/20 is your improper fraction, or 23/5 (simplified)
hope this helps