How do you calculate a percent of a number?
Percentages are found in many contexts beyond practice problems in math textbooks. One of the best examples is sale prices, which are often advertised as a particular percent off of a price. Tips on a restaurant bill are also thought of as percentages of a number. It is important to be able to both calculate the exact percent of a number for some problems and to estimate in your head the percent of a number in other contexts. Convert the percent to a decimal. This can be done very easily by moving the decimal point two spaces to the right. For example, 72 percent is converted to 0.72, 300 percent is converted to 3 and 4 percent is converted to 0.04. Multiply the number by the decimal. If you are told that 72 percent of all students have cell phones and there are 30 students in the class, you can figure out how many students will have cell phones by multiplying 0.72 times 30 to get 21.6. Round the answer if needed. Some problems require that the answer be rounded. If you are calculating
