use warnings;

for(10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9) {
  printf "%.3g\n", $_;
}

__END__
Outputs:

10.1
10.2
10.3
10.4
10.5
10.6
10.7
10.8
10.9