BUILT-IN WOLFRAM LANGUAGE SYMBOL
is a special symbol that is returned as the result from a calculation that has been aborted.
$Aborted is returned by a calculation that was aborted:
$Aborted is returned by TimeConstrained when a calculation exceeds its given time constraint:
$Aborted is returned by MemoryConstrained when a calculation exceeds its given memory constraint:
Try a computation with exact arithmetic and fall back to machine arithmetic if it is too slow: