#! /usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

sub amnt {
    my ($amount) = @_;
    say "$amount I'm checking amount before padding";

    my $padamnt = sprintf("%016d",$amount);
    say "$padamnt I'm checking amount after padding";
}

amnt(1/3);

##</code><code>##

2 I'm checking amount before padding
0000000000000001 I'm checking amount after padding