This document discusses the natural logarithm (ln) and its relationship to the mathematical constant e. It provides examples of how to calculate ln of different values with and without a calculator. It also describes laws of logarithms like ln(ab) = ln(a) + ln(b) and how to solve exponential equations using logarithms by changing the operation to multiplication or division. Examples are given of finding the value of x in equations involving natural logs and the constant e.