use strict;
use warnings;

foreach (3.5, 2.6888, 8.25 ,8, 1249.7999999999999999)
{ 
  printf("%.3f\n", $_);
}
__END__
3.500
2.689  note <= rounding up from 2.6888
8.250
8.000
1249.800 <= note rounded up from 7999999999999