Insight :E is an irrational number that cannot be written as a simple fraction.

Insight :E is the base of the natural logarithm function, which is useful for modeling exponential growth and decay.

Insight :E is also the value of the exponential function e^x at x=1, which has the property of being its own derivative.

Insight :E can be calculated as the limit of (1+1/n)^n as n approaches infinity, or as the sum of the infinite series 1/0! + 1/1! + 1/2! + 1/3! + ...