Notes on Logarithm by NUS:
Logarithms appear in all sorts of calculations in engineering and science, business and economics.
Before the days of calculators they were used to assist in the process of multiplication by replacing the operation of multiplication by addition. Similarly, they enabled the operation of division to be replaced by subtraction. They remain important in other ways, one of which is that they provide the underlying theory of the logarithm function. This has applications in many fields, for example, the decibel scale in acoustics.
In order to master the techniques explained here it is vital that you do plenty of practice exercises so that they become second nature.