Math / regex issue on math

When i use 11186.89, 6101.85  for values, the display of label is:

17,288.739,999,999,998

If i use

11186.83, 6101.85

i get 17,288.68

Once i do 

11186.84, 6101.85

17,288.690,000,000,002

Any  fix to this aside from using integer/rounding?
