use strict;
use warnings;

my $num = 0.05;
my $num_string = sprintf("%e", $num);
print "$num_string\n";
my($mantissa, $exponent) = split /e/, $num_string;
my $new_exp = $exponent + 4;
my $new_mantissa = $mantissa * 10**$new_exp;
print $new_mantissa, "e-04\n";
__DATA__
5.000000e-02
500e-04