Defining a Percentage
A percentage is a way of expressing a number as a fraction of 100 (per hundred). It is often denoted using the percent sign "%". For example, 50% means 50 out of 100. It helps us understand parts of a whole in a standardized way, making comparisons and calculations clearer.
How Percentages Relate to Fractions and Decimals
Percentages are directly convertible to fractions and decimals. To convert a percentage to a decimal, divide it by 100 (e.g., 75% = 0.75). To convert to a fraction, place the number over 100 and simplify (e.g., 75% = 75/100 = 3/4). This interconversion is crucial for performing calculations involving percentages.
Practical Applications of Percentages
Percentages are widely used in daily life and various fields, from mathematics and science to finance and retail. They help calculate discounts in stores, interest rates on loans, grades on tests, statistics in reports, concentrations in chemistry, and growth rates in biology. They provide a simple, universal way to compare quantities relative to a total.
Calculating a Percentage of a Quantity
To find a percentage of a given quantity, convert the percentage to a decimal or fraction and then multiply it by the quantity. For instance, to find 20% of 300, you would calculate 0.20 * 300 = 60, or (20/100) * 300 = 60. This method is fundamental for applying percentages to real-world problems.