In this paper, we present our work on creating a complete set of rules for temporal arithmetic mixing months and days based on the "history-dependent intuition". Many examples are presented for demonstrating how the rules are used and how the computations satisfy various desired arithmetic properties, such as the subtraction, commutativity and associativity properties. A notion of "days lost" (DL) is proposed to concisely keep track of the history of the temporal arithmetic computation and explain possible inconsistencies in terms of different desired properties.