oracle convert to number

Question

I am trying to convert 193 to 1000000193 in oracle. 193 could be any number less than 1000000000

This does not work.

select to_char(193,'1000000000') from dual;

Answer 1

i suppose this works.

select '1' || LPAD('193',9,'0') from dual

Answer 2

Why can't we add them?

select 193+1000000000 from dual;