1. It is a mitzvah to count both the days and the weeks. Therefore, on the seventh day one says; “Today is seven days, which are one week, of theOmer,” and on the eighth day one says: “Today is eight days, which are one week and one day, of theOmer,” and so on in this manner until day forty-nine (Shulchan Aruch489).
2. If one counted only the days and not the weeks, some say that (after the fact) he did fulfill his obligation, while others maintain that he did not fulfill his obligation whatsoever. Therefore, he should re-count that day properly, but without reciting the blessing. Nevertheless, even if he did not count again, he may continue counting on the subsequent nights with the blessing. However, if one counted only the weeks but not the days, such as on the seventh day he said only “Today is one week,” all agree that he did not fulfill his obligation (Mishnah Berurah 489:7).
