A decimal point is a symbol used in mathematics to separate the whole number part from the fractional part of a number. It is represented by a dot (.) and is essential for expressing numbers that are not whole, such as 0.5 or 3.14. The position of the decimal point determines the value of the digits that follow it. In the decimal system, each digit to the right of the decimal point represents a fraction of ten. For example, in the number 2.75, the 7 is in the tenths place, and the 5 is in the hundredths place. This system allows for precise representation of values in various fields, including science and finance.