Rating Newest Oldest. Best Answer: 12.5/1 is a fraction. if you are looking for a whole number fraction, such as 25/2 you can simply keep multiplying the first fraction by 1 such as 1/1, 2/2, 3/3. all are still equal to 1 and thus change only the form and not the amount 25 over 2, (25/2), 25 halfs = 12.5.Source(s):ou can figure that 12.5 is the numerator and the denominator is 1 Now, you can also figure that 12.5 times 2 is a whole number, so the muber 2 becomes the denominator of the fraction. the numerator would be x.