Feeds

What's 77.1 x 850? Don't ask Excel 2007

65,535 = the Number of the Beast

Secure remote control for conventional and virtual desktops

A Microsoft manager has confirmed the existence of a serious bug that could give programmers and number crunchers a failing grade when relying on the latest version of Excel to do basic arithmetic.

The flaw presents itself when multiplying two numbers whose product equals 65,535. Fire up your favorite calculator and multiply 850 by 77.1. Through the magic of zeros and ones, you'll quickly get an answer of 65,535. Those using the Excel 2007, however, will be told the total is 100,000. The program similarly fails when multiplying 11 other sets of numbers, including 5.1*12850, 10.2*6425 and 20.4*3212.5, according to this blog post from Microsoft manager David Gainer.

He stressed that the bug, which was introduced when Microsoft made changes to the Excel calculation logic, occurs only in the value Excel displays in a cell. The result stored in memory is correct. "Said another way, 850*77.1 will display an incorrect value, but if you then multiply the result by 2, you will get the correct answer," Gainer wrote.

Of the 9.214*10^18 different floating point numbers that Excel 2007 can store, six of them are susceptible to the flaw.

We're still at a loss as to why the latest and greatest version of Excel would get tripped up on equations totaling 65,535. The number, of course, is the highest that can be represented by an unsigned 16 bit binary number, so people who muck around with computers encounter it on a daily basis. For example, Internet protocol supports 65,535 TCP and UDP ports.

Microsoft engineers are in the final phase of testing a fix. It should be available for download soon, Gainer said. ®

Security for virtualized datacentres

More from The Register

next story
Netscape Navigator - the browser that started it all - turns 20
It was 20 years ago today, Marc Andreeesen taught the band to play
Sway: Microsoft's new Office app doesn't have an Undo function
Content aggregation, meet the workplace ... oh
Sign off my IT project or I’ll PHONE your MUM
Honestly, it’s a piece of piss
Return of the Jedi – Apache reclaims web server crown
.london, .hamburg and .公司 - that's .com in Chinese - storm the web server charts
NetWare sales revive in China thanks to that man Snowden
If it ain't Microsoft, it's in fashion behind the Great Firewall
Chrome 38's new HTML tag support makes fatties FIT and SKINNIER
First browser to protect networks' bandwith using official spec
Admins! Never mind POODLE, there're NEW OpenSSL bugs to splat
Four new patches for open-source crypto libraries
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Cloud and hybrid-cloud data protection for VMware
Learn how quick and easy it is to configure backups and perform restores for VMware environments.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.