Multiply the whole number portion of the percent by the denominator of the fractional part. For example, with 5 1/2 per cent, multiply 5*2 = 10.
Add this product to the numerator of the fraction. Continuing with the example from above, we would add as follows: 10 + 1 = 11.
Write that as the numerator of a fraction with the original denominator. In this example, we would write 11/2.
Write a new fraction with that fraction as the numerator and 100 as a denominator. In the example, we would write (11/2)/100.
Divide the fractions. Remember that 100 = 100/1, and that to divide fractions, you invert the denominator and multiply, so (11/2)/100 = (11/2)/(100/1) = 11/2*1/100 = (11*1)/(2*100) = 11/200.
Simplify if possible. You can simplify a fraction if the numerator and denominator have factors in common. The numbers 11 and 100 do not have factors in common, so this is the final answer in the example.