Decimal notation is a way of representing numbers using a base-10 system, which includes ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. In this system, each digit's position represents a power of ten, allowing for the expression of both whole numbers and fractions. For example, the number 345.67 consists of the whole number 345 and the decimal fraction 0.67. In decimal notation, the point that separates whole numbers from fractions is called the decimal point. This notation is widely used in everyday life, such as in currency, measurements, and scientific calculations, making it an essential part of mathematics and communication.