Names of the days of the week the "first day". This convention is also found in some Austronesian languages whose speakers were converted to Christianity by European missionaries. In Slavic languages, some of the names correspond to numerals after Sunday: compare Russian "vtornik" "Tuesday" and "vtoroj" "the following", "chetverg" "Thursday" and "chetvertyj" "the fourth", "pyatnitsa" "Friday" and "pyatyj" "the fifth"; see also the Notes. In Standard Chinese, the week is referred to as the cycle of the stars (). The modern Chinese names for the days of the week are based on a simple numerical sequence. The word for "week" (which is literally translated to "star day")
Determination of the day of the week ISO 8601. The day designated with 7 may also be counted as "0", by applying the arithmetic modulo 7, which calculates the remainder of a number after division by 7. Thus, the number 7 is treated as 0, 8 as 1, 9 as 2, 18 as 4 and so on. If Sunday is counted as day 1, then 7 days later (i.e. day 8) is also a Sunday, and day 18 is the same as day 4, which is a Wednesday since this falls three days after Sunday. The basic approach of nearly all of the methods to calculate the