Factorial

Score: 67.13 (pass)

#!perl -l
for(($t=1)..pop){$_*=$t;$t=(/(\d*[^0])0*/)[0]%1000000}print$t%10

Score: 86.13 (pass)

#!perl -l
$p=1;for(1..$ARGV[0]){$f=$_;while(!($f%5)){$f/=5;$p/=2}$p%=100000;$p*=$f}print$p%10