MidotKub imitates the four sets of numbers 1-13 of the game Rummikub. Thirteen is a common number in Judaism, found in the 13 Principles of Faith of the Rambam, the 13 Attributes of Mercy, the 13 Methods of Interpretation of the Torah, and Echad Mi Yodea from the Pesach Hagaddah. At Netivot, fourth through sixth grade students have been working on learning each of these four lists well so they can play MidotKub incorporating all of them.