Perl uses separate operators for mathematical addition and string concatenation.

  1 + 1 == 2;
  1 . 1 eq 11;

It uses separate operators for most mathematical and string operations, for that matter. There isn't much of a meaningful difference between strings and numbers in Perl -- it converts between then depending on the operation.

I suppose there's some type inference there and you'll get the default be 0 since 1 is also an integer, not a string.