FractionalPart[
x
]
+
IntegerPart[
x
] is always exactly x.
FractionalPart[
x
] yields a result when x is any numeric quantity, whether or not it is an explicit number.
Example: FractionalPart[Pi^2].
For exact numeric quantities, FractionalPart internally uses numerical approximations to establish its result. This process can be affected by the setting of the global variable $MaxExtraPrecision.
; FractionalPart[2.6]
