Decimal

Decimal or denary is a positional numeral system with a base of ten.

Decimal notation
Decimal notation is expressed using ten digits most commonly represented by the symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. Each of these ten values corresponds to a unique value which, when raised to some power of ten, can represent a single digit in a decimal number. Most commonly numbers expressed in decimal notation have the least significant digit last, for instance:

123 = 1 * 102 + 2 x 101 + 3 x 100