Factorial

Score: 52.12 (pass)

Slowly chipping away at it.

#!perl -l
$z=1;($z=$z*$_%1e7)=~s/0+$//for 2..pop;print$z%10

Score: 52.13 (pass)

Playing around with ways to shorten. Not getting very far.

#!perl -li1
($^I=$^I*$_%1e7)=~s/0+$//for 2..pop;print$^I%10

Score: 56.13 (pass)

#!perl
$p=1;$p*=$_,$p=~s/0+$//,$p%=1e6for(2..pop);print$p%10,$/

Score: 67.14 (pass)

Lame, but wanted to get on the board.

#!perl

$p=1;$p*=$_,$p=~s/.*?(\d{1,5}[^0])0*$/$1/for(1..pop);print$p%10,"

"