You are describing the general concept of a 'Dispatch Table'. While very useful at times I think that's a little overkill here. Your subroutines do exactly the same thing - add a number - and only this number differs. So why not just store the number as proposed by VSarkiss. Your code would then simplify to

my %lookup = ( # no longer a dispatch
   g6 => 1,
   g7 => 1,
   g8 => 1,
   g9 => 1,
   g0 => 0.5,
# ...
   );

my $total = 10;
$total += exists($lookup{'g6'})? $lookup{'g6'} : 0;

print $total, "\n";
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I think I still prefer the regex solution by enoch in this easy case where the keys/answers are so 'handy' to match.

-- Hofmator