1.NounFor 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."