Exponentiation

Exponentiation is a fundamental way to combine numbers.
It is easy to define for ordinary numbers :
just as 4 x 3 is 4 added to itself three times (4 + 4 + 4 = 12),
so 4³ is 4 multiplied by itself 3 times
(4 x 4 x 4 = 64).

But for transcendental numbers this definition of exponentiation is more complicated :
what could it mean to multiply something by itself  pi  times , for example?
That is because  pi  itself cannot precisely be defined, therefore  pi  multiplied by  pi  is also not precisely defined.