Field Calculation to split Address Field

I have a table of addresses that I need to split. The difficulty I'm having is that some of the addresses associated with a street have 2-digits up to 4-digits.

How would I get a uniform table from this:

Addresses:
111 Main St.
21 Main St.
3 Main St.

To this:

Number:
111
21
3

Street:
Main St.
Main St.
Main St.


Thanks!