If n is not an integral power of 10, then it is not easy to calculate log n But mathematicians have
made tables from which we can read off approximate value of the logarithm of any positive number
between 1 and 10 And these are sufficient for us to calculate the logarithm of any number expressed
in decimal form For this purpose, we always express the given decimal as the product of an integral
power of 10 and a number between 1 and 10