The decimal point is used to separate the whole part of a number from the decimal part. The whole part is represented using number digits to the left of the decimal point and the decimal part is represented using digits to the right of the decimal point.
The number digits to the left and the right part of the number have significance, the position of each digit indicates the magnitude of the digit.
For example, the number is written using the decimal point notation and can be expanded as the summation of each digit with its corresponding magnitude.