Q. In some shuls they have the minhag to sing and dance during Simchas Torah “Mechayei Mesim Ato… – Mashiv Haruach” (the blessing we begin to recite on Shemini Atzeres, asking for rains) 90 times.
This is done to become accustomed and habitual on saying it and when in doubt if one said it or not, we will assume it was said and the Shemoneesrei will not have to be repeated. Since this Niggun is usually divided into two dances, one in the night and one during the day of Simchas Torah.
If one only took part in one can he then just add 15 regular days to complete during davening the other 45 times?
A. Horav Shlomo Miller’s Shlit’a opinion is that it can be done.
(Some years ago, the Rov mentioned that if a singer had already made Kiddush during the day and drank wine or liquor, that counting may not be effective anymore).
Rabbi A. Bartfeld as revised by Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a.