I today had a strange "bug?" showing up. In one of our clients' applications there is a calculation that calculates the amount of hours that need to be worked every month. It counts the amount of days that they are supposed to work on, multiples it by the needed hours for a day and then uses a percentage to calculate how many hours really need to be worked.

Thus:

If you have 14 days to work that month it's 8*14 = 112 hours. If you do work 100% it should return 112 after you do the math 112/100*100. 

For some reason that gave a bug, the used needed to work 112,000000001 hours instead. I've made a small jsfiddle to point out the issue a bit better. I've there ran a test with 13000 numbers returning a lot of strange ones.

(results go in the console)

Does anyone know why this isn't returning the right number and it adds 0,0000...001 or sometimes substract something like that?