# Base

(1) In a number of system, the base is the number of distinct digits used to represent numbers. (2) In a logarithm, the base is the number with respect to which the power operation is inverted to form the logarithm. (3) In a geometric figure, the term base is used to refer to the bottom edge or surface.

Base is a middle school-level concept.

### Examples

Binary: | Binary refers to the "base 2" method of counting, in which only the digits 0 and 1 are used. |

Decimal Expansion: | The decimal expansion of a number is the usual "base 10" representation of a real number. |

### Prerequisites

Integer: | An integer is one of the numbers ..., -2, -1, 0, 1, 2, .... |