A number that is used to define a system of logarithms.

### Notation

The expression “log_{b}(*a*)” is the logarithm of a number *a* with base *b*.

### Examples

Example 1: In the expression “log_{2}(8) = 3”, the base is 2 and 2^{3} = 8.

Example 2: In the expression “log_{10}(100) = 2”, the base is 10 and 10^{2} = 100.