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Each option has a selection for the method and an input for the precision to use. Precision is the number of places to the right of the decimalvalue you want to round to (such as 0.125 if you want values rounded to an 8th of an inch).
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There are six methods for rounding:
None will do no rounding and use exact calculated values.
Round will use typical rules for rounding a value up or down.
Round down will always round down to the specified precision.
Round up will always round up to the specified precision.
Away from the nearest end will locate the nearest end and then round so the new location is further from it.
Towards the nearest end will locate the nearest end and then round so the new location is closer to it.