Logarithm

Noun

1. For a number x {\displaystyle x} , the exponent by which a given base number must be raised in order to obtain the power x {\displaystyle x} . Written log b ⁡<!-- ⁡ --> x {\displaystyle \log _{b}x} . For example, log 10 ⁡<!-- ⁡ --> 1000 = 3 {\displaystyle \log _{10}1000=3} because 10 3 = 1000 {\displaystyle 10^{3}=1000} and log 2 ⁡<!-- ⁡ --> 16 = 4 {\displaystyle \log _{2}16=4} because 2 4 = 16 {\displaystyle 2^{4}=16} .

   "For a currency which uses denominations of 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, etc., each jump in the base-10 logarithm from one denomination to the next higher is either 0.3010 or 0.3979."