Calculate a percentage of an amount, discounts, percentage increases, and other values. Learn how to calculate percentages with formulas and examples. Use a period as the decimal separator.
of
=
-
=
+
=
is
of
is
is
You might be interested in:
A percentage represents a part or fraction of a whole in relation to 100. For example, if we say that 25% of a cake has been eaten, we mean that one-quarter of the cake has been eaten.
The term "percentage" comes from the Latin "per centum," which means "per hundred." In mathematics, it is used to express a part of a whole in relative terms to a hundred. Therefore, a percentage is a way to represent proportions and compare different quantities. For example, if we say that 20% of a class passed an exam, we are expressing that out of every 100 students, 20 were successful.
The calculation of percentages is based on the following formula, which has its roots in the rule of three in mathematics:
The rule of three is a mathematical principle that helps us solve proportions. For example, to find 20% of 200, multiply 200 by 0.20. The result is 40.
The formula is fundamental to understanding how parts relate to wholes and how to express that relationship in terms of a percentage. It is a powerful means to compare, assess, and make decisions based on proportions.
Percentage problems are a fundamental part of everyday life. Through these solved examples, you can understand how to apply percentages in everyday situations, from calculating discounts on purchases to determining salary increases. These exercises will provide you with the necessary tools to master the world of percentages and use them effectively in your personal and professional life.
Statement: 20% of a number is equal to 40. What is that number?
Solution: To find the number, first convert the percentage to a decimal fraction (20% = 0.20). Then, divide 40 by 0.20: (40 / 0.20 = 200). Therefore, the number is 200.
Statement: If 15% of a monthly salary is $450, what is the full monthly salary?
Solution: To find the full monthly salary, convert the percentage to a decimal fraction (15% = 0.15) and solve the equation (0.15x = 450), where "x" is the monthly salary. Divide both sides by 0.15 to get (x = 450 / 0.15 = 3000). Therefore, the full monthly salary is $3000.
Statement: A t-shirt with an original price of $40 has a 25% discount. How much does the t-shirt cost after the discount?
Solution: First, calculate the discount. 25% of $40 is (0.25 × 40 = 10). Subtract that value from the original price: (40 − 10 = 30). So, the T-shirt costs $30 after the discount.
Statement: A mobile phone is priced at $500, but it has increased by 15%. What is the new price?
Solution: To find the new price, first calculate the increase. 15% of $500 is (0.15 × 500 = 75). Then, add that value to the original price: (500 + 75 = 575). The new price is $575.
Statement: If 30% of an unknown number is equal to 60, what is that number?
Solution: Similar to the first exercise, convert 30% to a decimal fraction (30% = 0.30) and solve the equation (0.30x = 60), where "x" is the unknown number. Divide both sides by 0.30 to get (x = 60 / 0.30 = 200). So, the number is 200.