Calculation Bug

[ih8l8nc]

Version: 2008
Operating System: Mac OS X 10.6 (Snow Leopard)
Processor: Intel

I was doing a homework problem and believe I found a bug. Another student in my MBA program got the same behavior. I am getting two different results from the same calculation.

Contents of cell B19: 8% (formatted as a percent and confirmed by stretching out 8 decimal points that the value is set to 8.00000000%)
Contents of cell C20: 1 (formatted as a number, and confirmed by stretching out 8 decimal points as 1.00000000).
Formula in cell c22: =1/(1+B19)^C20
Value in cell c22:.92521360

Using a calculator to figure out 1/1.08=.92592593

As you can see, from the third significant digit onward, Excel is returning the wrong value for the calculation. It seems like no big deal, but I am projecting 25 years of discounted cash flows and every one of them is wrong by a little bit so my total is off by a reasonable amount. As I said, I have a colleague in my class who is also using Excel for Mac and had the same problem. Only discovered when comparing totals with other people who used Excel for Windows.

 

[CyberTaz]

Sorry, but I can't repro your "error" here ‹ both the formula as written &
the calculator version provide a result of 0.925925926 (more precisely,
0.925925925925926). Formatting has no effect on the result & I get the same
answer in Excel 2004 as well.

Since you didn't give the specifics I'd first suggest that both you & your
fellow student make sure you have Office & OS X fully updated (12.2.1 &
10.6.1 respectively), restart the Macs & see if there's any change. Also,
try in a new blank workbook & see if you get the same result.

Regards |:>)
Bob Jones
[MVP] Office:Mac

 

[CyberTaz]

Just out of curiosity I tried your steps on a G5 -- was testing on an Intel
Mac yesterday. Same 2 versions of Excel, OS X 10.4.11 on the G5 also
produced the accurate result. I don't know what it is, but there appears to
be something of local origin on the systems or in the file you're using.

Regards |:>)
Bob Jones
[MVP] Office:Mac