If you want some textual representation of the expression and you don't care how exactly does it look like, you can use
ToString(). All of the
Expression types override this method.
For example, for the simple expression
num => num < 5,
num => (num < 5). But for more complicated expressions, it doesn't look like C# code anymore. For example, for
num => num < Math.Pow(5,5), it returns
num => (Convert(num) < Pow(5, 5)).