Mathematics is a field of human exploration and discovery, where abstract thought meets practical reality head on. This has resulted in countless equations, numerous in-depth forms of study (such as algebra, geometry, calculus, statistics, topology, homology, and so forth), and the creation or discovery of numbers with very specific mathematical numbers. Here are the most fascinating numbers in math.

Pi is the best known of the fascinating numbers. Many even have the first portion of this sequence (3.14159) committed to memory. Pi has more practical application than almost any other single irrational number, and is used for calculations involving abnormally shaped or round objects. This makes it fundamental in modern engineering.

The number known as “e” is named after the Leonhard Euler, who originally discovered it. This number has vast implications in modern business and investment, as well as growth mathematics. The irrational number e begins with 2.718, and represents the maximum end result for an item that grows off of its own gains.

Let’s take a simple example of what this means and how it applies. Let’s say that you invested a thousand dollars in a banking institution, and their growth rate allowed that thousand dollars to become two thousand dollars over the course of twelve months. Leaving it there for twelve months is insufficient, however, for maximum results. Simply withdrawing it after six months and immediately redepositing the new amount, for example, would increase your end total by $250. E is the top result possible here. In this case, it would mean $2718 after a year, with appropriate deposits and withdrawals.

The final number we will discuss today is the number i, or the symbol for the square root of negative one. This number began seeing use in the 1800s as different physical phenomena were being analyzed for their complex mathematical properties. The math behind electricity and electric circuits, dampening fields, flowing fluid, object resilience, and more are best understood through imaginary numbers. Even in study where i is not strictly necessary, it can be used to dramatically simplify bulky or complicated problems.