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Saying the word “Hayom/Today”:
One must say the word “Hayom/Today is” prior to counting the days. If one counted the amount of days without [first] saying “Hayom/Today is” [i.e. he plainly said “6 days to the Omer”], he does not fulfill his obligation and must thus repeat the counting with a blessing.
 Admur 489/7 and 14; Taz 489/7; M”A 489/9; Mamar Mordechai 489/6; Shalmei Tzibur p. 296; Derech Hachaim 9; M”B 489/20; See Kaf Hachaim 489/53
Other opinions: Some Poskim rule that even if one did not say the word “Hayom/Today” he fulfills his obligation. [Elya Raba 489/13; Chok Yosef 489/18; Mamar Mordechai; See Kaf Hachaim ibid; Shaar Hatziyon 489/25]
 The reason: As since he plainly stated a random amount of days without mentioning its connection to the current days, it is invalid, as the Torah states “Count 50 days” which means that the day itself must be counted by one saying “Today is such and such day” [Admur ibid]