What’s the problem to which this is a solution?
The Rule of 72 deserves to be better known among technical people. It’s a widely-known financial rule of thumb used for understanding and calculating interest rates. But others, including computer scientist and start-up founders, are often concerned with growth rates. Knowing and applying the rule of 72 can help in developing numerical literacy numeracy around growth.
For example, consider Moore’s Law, which describes how “the number of transistors that can be placed inexpensively on an integrated circuit doubles approximately every two years.” If something doubles every two years, at what rate does it increase per month, on average? If you know the rule of 72, you’ll instantly know that the monthly growth rate is about 3%. You get the answer by dividing 72 by 24 (the number of months).
