What they are: A logarithm is the exponent you raise a base to in order to get a number, acting as the inverse of exponentiation. Why they matter: They simplify multiplication, division, and roots ...

A scientific calculator has two 'log' buttons on it. These are marked log and ln. The log key is used for calculations of the form \({\log _{10}}x\). For example, to work out that \(\log 10000 = 4\) ...