Question 318300
Logarithm is an unfortunate name for what is actually the exponent.
eg:

{{{10^2 = 100}}} so log(100) = 2  --- the exponent is 2.
{{{3^4 = 81}}} so {{{log(3,81) = 4}}} --- 4 is the exponent.
Often just explaining that logarithm is actually the exponent makes it much clearer.
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As for finding it, most calculators have a Log button for "common logs", which is base 10.  The log is the exponent that 10 is raised to to get the number, or argument.
Most also have a natural log button, ln, which is base e.  More about that later.
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If you need to find a log with some other base, use the base change method, eg,
{{{log(5,66) = log(66)/log(5)}}}
That'll give the the exponent which will raise the base (5) to be 66.
{{{log(5,66) = 2.603179}}}
{{{5^2.603179 = 66}}}