Who knows ninety?

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.


Sara was 90 years old when she had Yitzchak


One who has already recited Mashiv HaRuach U'Morid HaGeshem (or any of the season-dependent phrases in Shmoneh Esrei) 90 times, no longer needs to worry that he forgot to say it.


Every Jew who left Mitzrayim had at least 90 donkeys loaded with silver and gold from the Egyptians. This is given as one possible reason why firstborn donkeys, unlike other non-kosher animals, are subject to the mitzvah of Pidyon Petter Chamor. (Bechoros 5b)

(The meforshim discuss the apparent hyperbolic nature of the Gemara's statement.)


Number of amens you should answer each day. (See Mishna Brurah 6:4:13.)

  • 2
    P.S. is this the accepted way to cite a "s'if katan"? – Yosef Sep 14 '10 at 19:26
  • I'd use "6:13", myself. – msh210 Sep 16 '10 at 19:40

According to the original Torah law, a Jewish farmer need give "only one grain of wheat" for terumah, and 10% of the crop to the Levi for maaser rishon. He thus ends up keeping 90 percent of the produce in most years.

(By Rabbinical law, the minimum amount for terumah is 1/60 of the crop, with 1/50 being the average and 1/40 being a more generous amount. He therefore keeps about 88 percent.)

  • Pea is also a single grain according to Torah law IIRC, supporting your 90 (though it's actually a smidgen less than 90, of course). (Pea does change the 88 to some lower number, though. I forget what the required amount is.) – msh210 Sep 16 '10 at 19:40
  • For a moment there I wasn't sure what you meant by "Pea," but then it hit me - you mean פאה. (It's usually transliterated with a final h.) So good point - I forgot about that. Peah is also 1/60 by Rabbinical law, so that would leave 86 or 87 percent for the farmer. – Alex Sep 16 '10 at 23:33

The age at which a person no longer has gevura and the time he should start honing his avodas Hashem (Pirkei Avos 5:21, Gra; R' Akiva Eiger/Rabbeinu Yona 'ben Tishim laSuach')


representing the Hebrew letter tsadii, the first letter of the word tsadik- (righteous) why does this word start with this letter one reason we learn is that the because of merit of the rightous this world is existing, if we look at the letter tsadii it is a letter nun bent over with a yud atop as are the rightous bent over to carry unto themselves the burden of the yisroel which begins with yud.

  • 1
    While on the topic: Ksav Ari has the heads of the Tzadi facing away from each other; Ksav Beis Yosef has them facing each other. Heard from R' Hershel Shachter, machlokes mekubalim if the separate faces before Adam/Chava split were facing or separate, philosophical disagreement if it's "each for himself" (even before the first sin) or harmonious. – Shalom Sep 7 '10 at 0:30
  • thats interesting, well before adam was given chava they were back to back, only after did they become ponim ba ponim. – Koachyah Sep 8 '10 at 0:59

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