As we can see - in this case - Perl 6 does not care that you typed in a string, the numeric + adds together the two numbers.
Example 2-5. examples/scalars/add.p6
#!/usr/bin/perl6 print "First number:"; my $a = readline; print "Second number:"; my $b = readline; my $c = $a + $b; say "\nResult: $c";