share prices and rounding errors, cannot reconcile extra pennies

Mike or Penny Novack stepbystepfarm at mtdata.com
Sun Feb 23 10:15:34 EST 2014


>>
>>I am in the process of converting from Quicken 2007 to Gnucash 2.61.  I
>>was hoping that Gnucash would not have the rounding errors for share
>>prices that have always vexed me in Quicken, but no luck.
>>
>>The brokerage statement says:
>>
>>Buy 1377.41 shares of XYZ at $10.89/share = $15,000.00
>>
>>Both Quicken and Gnucash compute it at:
>>
>>1377.41 x 10.89 = $14,999.99  (one penny off, arrrgh...)
>>    
>>
This is a misunderstanding about rounding and significant digits and the 
calculation being considered backwards.

ALL of the numbers are being to whole cents/hundredths. It was NOT 
"given this price per share to the nearest penny and this number of 
shares to the nearest hundredth of a share compute the cost". It was 
"given this much spent buying the stock at this price per share, how 
many shares were bought to the nearest hundredth of a share.

In other words, you were assuming that if A / B = C then B * C = A even 
when rounding is involved. Not true. Not necessarily exactly equal.

15,000.00 / 10.89 = 1377.41  THAT was the calculation your brokerage 
performed.

Michael


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