e approximately equals 2.7182818284 (don't know any more digits)

no i'm pretty sure godzilla101 is correct

answer to AOPSUser's question:


Choose whatever way of writing it that you prefer.

e = 5

Now e is 5.

I deeply apologize that it has come to this.

AOPSUser:
Define the logarithm function as ln(x)=int(1 to x)dx/x, x>0. Call it's inverse function exp(x) (and confirm that the inverse exists), the constant e is now exp(1).
Alternatively, define exp(x) as exp(x)=Sum(k=0 to infinity)x^k/k!, e=exp(1) in this definition too.

billymills definition is simpler though, I prefer his/her answer to the question over mine.