Esrim - mi yodeya?

Question

Who knows twenty?

Please cite/link your sources, if possible. After about one business day, I will:

• Upvote all interesting answers.

• Accept the best answer.

• Go on to the next number.

Answer 1

20 are the gerahs in a shekel (Ex. 30:13).

Also, 20 silver denarii = the 5 shekalim needed for redeeming a firstborn son (Bava Metzia 44b and Rashi there).

Answer 2

Twenty is (the age) when one can be put to death! (by the hands of heaven as a punishment for a commandment that incurrs such a penalty.)

Answer 3

Twenty is the age of the Draft. (Numbers 1:3)

Answer 4

20 represents כתר, the highest of the Sefiros, since (a) the initial letter of כתר is כ, which equals 20, and (b) the numerical value of the word עשרים is 620, which equals that of כתר. (Likkutei Torah, Shir Hashirim 35c)

Answer 5

20 is the age when one can sell inherited real estate. (Hoshen Mishpat 235:9)

Answer 6

Twenty (point one) minutes are a "hiluch mil" (a Halachic time unit) according to Rabbi Ari Storch's reading of Tosfos.

(The common opinions are 18, 22.5 or 24 minutes instead.)

Answer 7

20 are the 10 commandments (two sets of luchot, and also twice listed in the Torah)