Percentages are just fractions in disguise. A percentage is just a fraction with denominator 100, and instead of writing the denominator, we write the percentage symbol %. (If you look closely at the percentage symbol you might even see there's the 1 and two zeros from 100 hiding in there!)

To calculate with percentages, just remember to include this implied denominator of 100 by dividing the percentage value by 100 to turn it into a regular number. With bar models we do this by dividing the whole into 100 equal parts.