Serious bug found in Excel 2007 ::: 850*77.1 = 100,000 and not 65535 | Hacker News Reader

Serious bug found in Excel 2007 ::: 850*77.1 = 100,000 and not 65535

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39 pointsnickb27 comments

somebody pointed out that Excel is storing the value correctly as 65535, but is setting the text as "100,000". Here's how to test. type the equation in cell A1. Hit Alt+F11, then CTRL+G to get to the "VBA Immediate Window". Type print Range("A1").Value and hit enter. You'll get 65535. If you do .Text instead, you'll get 100000.

Even better, If you make Cell A2 =A1*2, you get 131070. A3 =A1+1 yields 100001. Hmm. ;)

http://it.slashdot.org/comments.pl?sid=307215&cid=207394...

That seems like the most plausible theory I've seen so far.

Is it really "Serious" though? I mean, this isn't exactly devastating. Office 2007 has been out for almost a year and this being the first time we've heard about it seems to imply that not many users have run into this issue. It's poor that this got by their internal testing, but I'm not sure it's Serious.

Under infinite precision the probability of selecting this particular expression to evaluate is zero. Under finite precision it is small.

However, it raises the question of what other errors Excel has. Excel has had other serious mathematical errors in the past - like the standard deviation function. In Excel 97, if you wrote down a sequence of large numbers with a standard deviation much less than the mean (1e10, 1e10 + 1, ..., 1e10 + 10, say) it would say the standard deviation is equal to zero!

Furthermore it doesn't help that there's always a total lack of transparency in how Microsoft handles bugs. We have no way of knowing whether Microsoft knows about this, if or when they intend to fix it, and what other problems this could possibly hint it. Megalomaniacal megacorporations are so banal.

It's not just one expression, there's a whole family of expressions that should evaluate to 65535 which evaluate to 100000 under Excel 2007.

Well, how many have actually gone undetected? There are quite a few papers out there that show that Excel-induced accounting/financial errors are a lot more common than previously thought. Some financial services have gone as so far to prohibit the use of Excel in their financial planning and forecasting.

Check out some of the papers on Google Scholar for bibliography: http://scholar.google.com/scholar?hl=en&lr=&safe=off...

I guess Microsoft's valuation of Facebook was done in Excel. Can anybody check if 6,553,500,000 gives 10,000,000,000 ?

"Microsoft in recent weeks approached Facebook with proposals to invest in the startup that could value the fast-growing site at $10 billion or higher, said people familiar with the matter."

Who puts the valuation for Facebook? was it MS or WSJ assumption?

Any problem like this could be potentially very serious, when so many people around the world still use Excel for making important business decisions. Not being able to trust your numbers 100% is a big issue to some..

to all.

According to later posts on this, many calculations which involve storing 65535 or 100000 really store the other one:

Dana DeLouis writes: """

And if you multiply be say, 2 you get something else:

=A1 MUL 2 returns 131070, as if A1 had 65535. (which it should have been)

=A1 MUL 1 Keeps it at 100000.

=A1-1 returns 65534

=A1/1 is still 100000

=A1/2 retuns 32767.5 """

Given that it would more often be the case that 65535 or 100000 comes up as an intermediate number than the final result, it could be that there are many calculations that have been done in error silently for those using Excel 2007.

EDIT: Replaced asterisks with MUL because I don't know how to escape them.

New Arc suggestion: a Markdown/Textile implementation. :(

Is the formatting for news.yc documented anywhere, btw?

If it is, link plz.

Is PG neglecting his users?! And how is this?! So he's a bad teacher, not following his own advices. That's sad.

He is kinda busy, you know. This isn't a business. If he had neglected users at Viaweb that would be different.

(I just find it curious that any single user here has to guess how to do proper formatting.)

Probably not. All I know: using one star on each sides of something for italics, two for bold, and if you put a space at the beginning of a line, you get fixed-width font (for code).

and links get auto <a href>'d if you use the full http:// address

No bold here; two stars just cancel each other out.

I'd say it's fairly serious, since something so basic doesn't inspire a lot of confidence in Excel. It only takes one bad PR moment like this to tarnish a product's reputation forever.

I wonder if some disgruntled ex-Microsoft employee just took the crown for best Sabotage-By-Easter-Egg ever.

Funny thing is, 65,536 is 200,000 octal. They can't even make elegant mistakes.

Somehow I don't think the idea of an elegant mistake would go over very well with Ballmer. God damn philistine business people.

Uh, hello?!, this is a feature... somehow...

Not just a feature--it's my favorite feature! I charge clients $850 per day and make sure each contract lasts 77.1 days. Then I have them compute the total in Excel themselves(so they can be sure the amount is correct) and write me a check for $100,000. It's a feature!!

Microsoft calc.exe gets the answer right.

OpenOffice calc gets it right too.

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