A decimal is a number expressed in the base-10 numeral system. This system is the most commonly used numeral system and is based on powers of 10. The position of each digit in a decimal number signifies a specific power of 10. For example, the decimal number can be understood as:

The point that separates whole numbers from fractional values in a decimal number is called the decimal point. Everything to the left of the decimal point represents whole numbers, and everything to the right represents fractions of a whole.

For instance, in the number , is the whole number part and represents the fractional part. The number can be understood as:

Which can also be written as:

Decimals are essential in mathematics and everyday life as they provide a convenient way to represent and calculate with both whole numbers and fractions. They are especially crucial in contexts where precision is needed.