Writing 33 per cent as a fraction requires a basic knowledge of fraction and percentage conversion. A fraction represents an amount relative to a whole. With percentages, the same concept applies, with 100 designated as the whole. Checking your work requires an additional understanding of fraction-to-decimal conversion.
Recognise that a per cent represents a fraction, with the per cent as the numerator and 100 as the denominator. A numerator is the top number in a fraction, and a denominator is a bottom number.
Write down the number 33, with a line beneath it and 100 below the line. You should wind up with 33/100. You now have your fraction.
Check your work by dividing 33 by 100, to convert your fraction into a decimal. You should have 0.33. The number is equivalent to a percentage, without the decimal point. You will arrive at 33 per cent, the same number with which you started.
Round the number to simplify the fraction, if desired. The goal is to reduce the number as much as possible. You can do this by dividing 33 by 33, to arrive at a 1. Whenever a top number is divided, the bottom number must be divided by the same figure. Therefore, 100 must also be divided by 33. You will be left with 3.03 for the bottom number.
Round the bottom number to the first decimal place. Now you have 3. You are left with the simplified fraction of 1/3.
The simplified 1/3 is actually equivalent to 33 and 1/3 per cent. Some instructors will not allow students to round to this number. In this case, 33/100 is the accurate equivalent.