When you pay sales tax, determine how much an item costs on sale, or calculate your final mark in a course, you are applying concepts of percentages. A percent is a fraction with a denominator of 100. To show that a number is a percent, we use the percent symbol (%) beside the number. This module will help you understand what a percent is, how to convert between a percent, fraction, and decimal, and how to solve sales tax, commission, discount, and percent change problems. This module also covers place value and rounding in decimals.