When does the difference between a string and a number matter in Perl 5?

Question

If a string in Perl 5 passes looks_like_number, it might as well be a number. For instance,

my $s = \"10\" + 5;

results in $s

Answer 1

When dealing with bitwise operators. 123 ^ 456 is 435, but "123" ^ "456" is "\x05\x07\x05". The bitwise operators work numerically if either operand is a number.