Crazy Decimal Places

[DEI]

I am doing some summing in Queries and keep getting
numebrs with a large number of decimal places (Ex:
38.8500000000001).

The numbers in the tables these calculations are based on
have three decimal places at the most. I have tried to
change properties in the Table, Query, and even Report and
nothing seems to change the appearance of these values.

Is there something I can do?

 

[Marshall Barton]

I am doing some summing in Queries and keep getting
numebrs with a large number of decimal places (Ex:
38.8500000000001).

The numbers in the tables these calculations are based on
have three decimal places at the most. I have tried to
change properties in the Table, Query, and even Report and
nothing seems to change the appearance of these values.

Floating point (Single, Double) data types do not guarantee
100% accuracy, not even if you do the math with pencil and
paper (try to write down the decimal value of 1/3).

Generally, you can just ignore such small inaccuracies by
specifying a format with fewer decimal places and the number
will be rounded so you won't see these little discrepencies.