The calculations seems to be messed up. It doesn’t give the correct results.
For example, when I create one hidden field (field’s ID=100 for example) with a value of “1.6″
And then I create another field where I “Calculate the default value for this field”, using this formula for example:
where  is the ID of the hidden field.
And when I preview the form, it gives me a weird result for the calculated field. The result it gives is “489.59999999999997″
But when I try to use any calculator, the result should be exactly “489,6″
Any idea why it gives me the weird incorrect result?