for my $num ( 0 .. 101 ) { $num += 0.005; printf "%.2f\t%.20g\n", $num, $num; } #### 0.01 0.0050000000000000001041 1.00 1.0049999999999998934 2.00 2.0049999999999998934 3.00 3.0049999999999998934 4.00 4.0049999999999998934 5.00 5.0049999999999998934 6.00 6.0049999999999998934 7.00 7.0049999999999998934 8.01 8.0050000000000007816 9.01 9.0050000000000007816 10.01 10.005000000000000782 11.01 11.005000000000000782 12.01 12.005000000000000782 13.01 13.005000000000000782 14.01 14.005000000000000782 15.01 15.005000000000000782 16.00 16.004999999999999005