Holy Cow! Microsoft Doesn’t Know Simple Maths

by: - Last updated on: December 17th, 2016


Microsoft has been selling their Windows operating systems ever since 1993. That’s a good lord 17 long years. They have had more than eight different versions of Windows OS in those 17 years, and all of them were aimed to do simple & complex computing.

One such tool aimed to help us carry out simple computing is the Windows calculator. As with the OS itself, Windows calculator app has also undergone changes over the years and in the latest Windows 7, it is prettier than ever before. But there are few things which are left unchanged – Windows Calculator bugs!

Windows calculator bug -> 2-2 != 0

Trust me, if you haven’t come across this bug before, you will surely have a hearty laugh. Open the Windows calculator and find out the square root of 4. It gives the right answer (which is 2). Now subtract that with 2. Lo and behold! The answer is not 0 but -1.068281969439142e-19. You don’t trust me? Check it out yourself! Or check out the video below!

The funny thing is, in Windows XP, the result used to be -8.1648465955514287168521180122928e-39. So they have surely tried their best to come near zero ;)

Someone has registered the bug under MS connect, but no one from the team has bothered to address it yet!

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  1. Alok is right. All flating-point calculation (and sqrt is always such a case) will have a certain error margin. This is due to the fact that we use limited info to represent sets of numbers that, in essence, require infinite storage to be represented.

    Besides, the -8e-39 error margin is way smaller than -1e-19 . You should look first at the exponent (-39 is way smaller than -19) to compare the values. This shows that when in scientific mode the calculator uses more bits to represent numbers.