Pages

Sunday, July 19, 2009

Spreadsheet Miscalculation of 30!

Today, I encountered something amusing. I was trying to calculate Factorial 30 (also written as 30!). Don't ask me why I was trying to calculate Factorial. :-).

As a refresher for some of us who may have forgot Factorials, Factorial 30 is product of all positive integers between 1 and 30 inclusive.

30! = 30 x 29 x 28 x 27 x 26 x 25 x 24 x 23 x 22 x 21 x 20 x 19 ... x 1.

With Microsoft Excel, using both PRODUCT function and manual multiplication 30 x 29 x ....

30! = 265,252,859,812,191,000,000,000,000,000,000

Same results on my MacBook with Numbers program, using both PRODUCT function and manual multiplication.

30! = 265,252,859,812,191,000,000,000,000,000,000

I got slightly different result with Google Docs Spreadsheet, using PRODUCT function

30! = 265,252,859,812,191,030,000,000,000,000,000

And, another different result with Google Docs Spreadsheet using manual multiplication

30! = 265,252,859,812,191,100,000,000,000,000,000

But actually,

30! = 265,252,859,812,191,058,636,308,480,000,000

It appears spreadsheets are rounding numbers after 15 or 16 digits.

Sunday, May 31, 2009

Peril of Working in Cloud

Sorry! We are experiencing technical difficulties and cannot show all of your documents.


Do you have local backup copies of everything important you store in the Cloud?