Are you very specific about solving this with regex?
Instead of using substring or regex, I feel this approach is more logical. 
#!/usr/bin/perl -w
use strict;

my $num = 786603;
my $rem = $num % 100;
$num += (100 - $rem) if ($rem > 0);
print $num."\n";

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In reply to Re: Round up 3 values to the next 100 by Mandrake
in thread Round up 3 values to the next 100 by siva kumar

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