Simple Math Calculation is incorrect

Question

I have seen this topic here before but cant find it. When I
do the following script it returns an incorrect value;
var myNumber = 999.43
trace(myNumber-999) //returns: 0.42999999999995
So how can I retrieve the value .43? I suppose I can do this;
var myNumber = 999.43
var hundred = myNumber*100;
var whole = hundred-99900;
trace(whole*.01) // returns: .43
But is there a better way? And why is it that Flash is
calculating like this?

Answer 1

the reason for the apparent error is because flash is
performing arithmetic on a binary computer. within the limits of
flash'es accuracy (16 digits),
0.42999999999995 = .43
to eliminate those errors, you can use integer arithmetic or
the flash string methods. integer arithmetic is probably preferable
if you're doing arithmetic operations.