Decimals are a way to represent numbers that are not whole. They use a decimal point to separate the whole number part from the fractional part. For example, in the number 3.14, the "3" is the whole number, and ".14" represents a fraction of a whole. Decimals are commonly used in everyday life, such as in money, measurements, and statistics. Decimals can be converted to fractions and vice versa. For instance, the decimal 0.5 is equivalent to the fraction 1/2. Understanding decimals is important for tasks like budgeting, cooking, and calculating distances, making them a fundamental part of mathematics and daily activities.