hyperoperations are one mathematical way to process numbers, and include:
and roots (like the square root)
you see, multiplication is repeated addition:
3*4=12 , 3+3+3+3=12
and powers are repeated muliplication:
3^4=81 , 3*3*3*3=81
and subtraction and division and roots are their inverses:
4th root of (3^4)=3
so what if you continue this pattern?
well, repeated exponentiation (powers) is called tetration (because it is the 4th hyperoperation),
3 tetrated by 4=7,625,597,484,987 and
tetration also has corresponding hyperroots and hyperlogarithms as inverses.
repeated tetration is pentation, and you can keep going forever from there.
http://en.wikipedia.org/wiki/Knuth’s_up-arrow_notation (for one way of writing all this)