section_path: Calculations/Keviah
section_name: Keviah
paragraph_text: Keviah
  
  There are three qualities that distinguish one year from another: whether it is a leap year or a common year; on which of four permissible days of the week the year begins; and whether it is a deficient, regular, or complete year. Mathematically, there are 24 (2×4×3) possible combinations, but only 14 of them are valid.
  
  Each of these patterns is known by a kevi'ah (Hebrew: קביעה for 'a setting' or 'an established thing'), which is a code consisting of two numbers and a letter. In English, the code consists of the following:
  
  The kevi'ah in Hebrew letters is written right-to-left, so their days of the week are reversed, the right number for 1 Tishrei and the left for 15 Nisan.
  
  The kevi'ah also determines the Torah reading cycle (which parshiyot are read together or separately.