$s1 = "01234567891233456789";
$s2 = "012345.6789123456789"; 

$n1 = $s1+1; 
$n2 = $s2+1; 

$c1 = $s1;
$c2 = $s2;

print "$n1 == $s1 + 1\n";
print "$n2 == $s2 + 1\n";
print "$c1 eq $s1\n";
print "$c2 eq $s2\n";

__OUTPUT__
1.23456789123346e+18 == 01234567891233456789 + 1
12346.6789123457 == 012345.6789123456789 + 1
01234567891233456789 eq 01234567891233456789
012345.6789123456789 eq 012345.6789123456789