What Is a Logarithm?

A logarithm is a type of function. There are multiple types of logarithms, but here we are looking at common logarithms.

Logarithms can seem a bit odd, but they are just a special definition of a number: The logarithm to the number $x$ is the number $n$ that you have to use so that $10^n=x$

Like this:

$$\begin{array}{llll}\hfill \log 1& =0\text{ because }10^0=1& \hfill & \\ \hfill \log 100& =2\text{ because }10^2=100& \hfill & \\ \hfill \log 0.001& =-3\text{ because }10^{-3}=0.001& \hfill & \end{array}$$