Chemical Thermodynamics of Tin - Volume 12 - OECD Nuclear ...

C.6 Procedures for data handling
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When adding or subtracting, the result is rounded to the number of decimal
places (not significant digits) in the term with the least number of places. In
multiplication and division, the results are rounded to the number of significant digits in
the term with the least number of significant digits.
In general, all operations are carried out in full, and only the final results are
rounded, in order to avoid the loss of information from repeated rounding. For this
reason, several additional digits are carried in all calculations until the final selected
data set is developed, and only then are data rounded.
C.6.4 Significant digits
The uncertainty of a value basically defines the number of significant digits a value
should be given.
Example: (3.478 ± 0.008)
(3.48 ± 0.01)
(2.8 ± 0.4)
(10 ± 1)
(105 ± 20).
In the case of auxiliary data or values that are used for later calculations, it is
often inconvenient to round to the last significant digit. In the value (4.85 ± 0.26), for
example, the “5” is close to being significant and should be carried along a recalculation
path in order to avoid loss of information. In particular cases, where the rounding to
significant digits could lead to slight internal inconsistencies, digits with no significant
meaning in absolute terms are nevertheless retained. The uncertainty of a selected value
always contains the same number of digits after the decimal point as the value itself.
CHEMICAL THERMODYNAMICS OF TIN, ISBN 978-92-64-99206-1, © OECD 2012