Who knows forty-five?

Please cite/link your sources, if possible. At some point in the next few days, I will:

  • Upvote all interesting answers.

  • Accept the best answer.

  • Go on to the next number.


6 Answers 6


45 are the days from the Exodus until the arrival of the Jewish People at Mount Sinai. Correspondingly, Hashem describes Himself (through the metaphor of the prophet Hosea's actions) as having acquired His spouse, the Jewish People, with "a chomer of barley and a lesech of barley" - totaling 45 se'ah. (Hosea 3:2 and Radak there)

  • 1 chomer + 1 lesech = 45 se'ah is almost exactly 18 bushels, by the way.
    – Shalom
    Commented Jun 1, 2010 at 18:40
  • Eh it all depends how you do the math. Let me say "it's between 12 and 24 bushels", that should cover it I think.
    – Shalom
    Commented Jun 1, 2010 at 18:48

Forty-five are the Amida blessings that you'll say on a "Friday" (using the non-Jewish definition of Friday): 19 for Friday Shachris, 19 for Friday Mincha, 7 for Shabbos Maariv.

Speaking of davening, forty-five are the minutes after 8AM at which many newer Centrist Orthodox synagogues on the East Coast begin services on Shabbos morning. Many older synagogues figured 9AM was a good time, but it turns out for the US East Coast that starting 15 minutes earlier can mean making Sof Zman Krias Shema (latest time for saying the Shema, the first quarter of daylight hours) much more often.

(I looked at a sunrise/sunset chart for Brooklyn. If my math is right, assuming 34 minutes from start to Krias Shema, the number of additional days a year at which you'll make Shema in time by switching from 9 to 8:45 is ... 45.)

Also, isn't there someone with the opinion that Shabbos ends 45 minutes after sunset (in New York)?


The shem מ״ה (that is, יו״ד ה״א וא״ו ה״א)


45 times the Torah warns us regarding a convert (e.g. to love, not cheat, not cause suffering)

corresponding to the

45 times the Torah warns us against idol worship.


  • Is this 48 or 45?
    – Shalom
    Commented Jun 1, 2010 at 17:45
  • The linked page does say 45 for both of them. Interesting, though, since the Gemara (Bava Metzia 59b) gives 36 or 46 about the convert; and if I recall correctly, Sefer Hachinuch says 44 about idol worship.
    – Alex
    Commented Jun 1, 2010 at 17:53
  • Interesting. I think I better start looking up the sources of this sefer.
    – Yahu
    Commented Jun 1, 2010 at 18:04
  • The Yalkut Shimoni that this sefer mentions does say 48 (at hebrewbooks.org/pdfpager.aspx?req=9758&pgnum=366, near the bottom of the second column).
    – Alex
    Commented Jun 2, 2010 at 1:17
  • Whoops for this sefer! Actually this part of the sefer is the hosafa of Noach Chaim Ben Moshe who unfortunatley did not do as accurate a job as one would hope. Here's the frontispiece: hebrewbooks.org/…
    – Yahu
    Commented Jun 2, 2010 at 16:35

45 are the amount of righteous people necessary to save the 5 cities in the region of Sedom, with the combination of Hashem being added for each city (Bereishis Rabba 49:9)


45 are the maximum Hallel days in a year (in the diaspora):

  • 8 Pesach
  • 2 Shavuot
  • 9 Sukkot + Sh'mini Atzeret
  • 8 Chanukah
  • Rosh Chodesh (source)

So that's 27 + Rosh Chodesh. How many of those are there?

The following months always have two days of Rosh Chodesh [...]: Cheshvan, Adar (and Adar II), Iyar, Tammuz, and Elul. The following months always have one day of Rosh Chodesh: Tishrei, Shevat, Nisan, Sivan, and Av. The months of Kislev and Tevet [...] some years both have two days. (source)

We don't celebrate Rosh Chodesh in Tishrei, and Rosh Chodesh Tevet falls in Chanukah so has already been counted. The others total 18.

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