*e*

The mathematical constant denoted *e* is the base of the natural logarithm which has value of approximately 2.718.

E is a high school-level concept that would be first encountered in a pre-calculus course covering exponents and logarithms. It is listed in the California State Standards for Algebra II.

### Prerequisites

Irrational Number: | An irrational number is a real number that cannot be written as a fraction. Irrational numbers have decimal expansions that neither terminate nor become periodic. |

Natural Logarithm: | The natural logarithm is the logarithm having base e. |