For example: if the rows with row numbers: 3,4 or 5 need to be marked.
These won't work (custom formula):
=ISNUMBER(MATCH(ROW();{3;4;5})) // marks all rows
=ROW()={3;4;5} // marks one row (#3)
As Saddles commented, the match()
formula is missing the third parameter. Use this conditional formatting custom formula rule instead:
=match(row(); { 3; 4; 5 }; 0)
See match().