Like most computer apps (COBOL is an exception), Excel uses the IEEE
convention for storing decimal numbers (numbers based on the fact we have 10
fingers) as binary numbers (computer memory has two states: on and off).
This results in a limitation on the number of digits that can be stored -
15.
But are you working with real numbers? Things like ISBN, telephone, etc
numbers re really not numbers in the sense that we never do math on them. In
this case you have two workarounds:
a) before entering the value format the cell as text
OR
b) preface the value with single quote (apostrophe) - this will neither
display nor print (visible only in the formula bar)
To learn more read:
What Every Computer Scientist Should Know About Floating Point
http://docs.sun.com/source/806-3568/ncg_goldberg.html
Go to source>>
http://www.cpearson.com/excel/rounding.htm
best wishes
