From the list below, select four situations in which casting is the preferred fabrication technique.

(1) when mechanical strength is not an important consideration
(2) for economical producing of parts that require very close dimensional tolerances (e. g. bushing and gears)
(3) for large pieces and/or complicated shapes
(4) for alloys having low ductilities
(5) when it is the most economical fabrication technique
(6) for metals having high melting temperatures