Use a Tk::Spinbox, see https://metacpan.org/source/SREZIC/Tk-804.033/examples/spinbox

See Re: can'yt figure out whats wrong in this code?, Re: Perl/Tk,How to limit the number of characters in Entry? and widget - Demonstration of Perl/Tk widgets, Entries and Spin-boxes: 3. Validated entries and password fields.

#!/usr/bin/perl --
use strict;
use warnings;
use Tk; 
my $mw = tkinit; 
for my $ix ( 0 .. 9 ){
    my $box = $mw->Spinbox(qw/
        -from -10 
        -to   10 
        -increment .01 
        -format %05.2f 
        -width 10
        /,
    )->pack ;
    $box->set( $ix );
}
$mw->WidgetDump;
MainLoop;
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