A short text from two manuscripts of Yerevan Mashtots Matenadaran was published. The text contains the explanation of some columns of “Kharnakhoran”- the set of calendar tables giving parallel presentation of calendars of 14 nations, originally composed by Anania Shirakouni. The columns “Roman epacts”, “Roman septenaries”, “Week letter” (shabatagir-շաբաթագիր) are explained. Besides, instructions are given how to use these columns in order to determine the days of new Moon, full Moon, and some important feasts as “Arajawor”, Quinquagesima, Easter, “Ashkharhamatran”, Assumption, Pentecost, Transfiguration etc. The analyze shows that the text was seriously edited and distorted (at least twice). Some explanations (formulas) are given using calendar realities appeared after Anania. Meanwhile, the analyze of the systems of Roman epacts and septenaries shows that these systems were originally been the same as used by Anania in his Calendar. This analyze and the fact that the text explains some columns of Anania’s Kharnakhoran show that the original of this text was formerly a component of Anania’s Calendar (Tomar) as a part explaining some columns of Kharnakhoran.