UC: If you draw a number line, you'll see that the unity for Z is 1, while the unity for R is only an infinitismal point. So by logic, you can jam up more of R into a space than Z.
It could also be proven by assigning each of the Infinite R to a Z, then come up with infinites more of R
EX:
1.245436267463... ----> 1
1.438651283955... ----> 2
1.436327554434... ----> 3
... to infinity
but, you can come up with more irrational numbers by taking the 1st digit +1 ( 9 would turn into 0) after the decimal of the 1st number, the 2nd digit of the 2nd number and so on. There you'll have a new irrational number:
1.347....
It can't be the first number since the first digit after the decimal is different, the same applies for the 2nd number and the 3rd.. and to the infinite.
And that's how you prove there is more than infinite.