IF formula returning FALSE when should return TRUE

[poikiloid]

Can't figure this one out...
See linked doc.
Simple IF. Should be true but gives false.

https://utexas.box.com/s/bnhebnluttsj0ihikk3b0coul47repbj

I've tried and read everything I could think of. Any help appreciated.
Thank you!!

 

[BobUmlas]

C1 is A1-B1 ansd evaluates to
4.01999999998952, whereas D1 has 4.02, so they ARE unequal.
Change your formula to =IF(ROUND(ABS(C1),5)=D1,"y","n")
This is because of computers using binary. arithmetic.

 

[poikiloid]

Thanks so much, Bob!
ROUND() worked!
Weird that excel is actually generating a number different from what you'd expect, due to binary arithmetic.