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
Week of Prayer for Christian Unity week of prayer, for example around Pentecost (as originally suggested by the Faith and Order movement in 1926, and Pope Leo XIII in 1894), which is also a symbolic date for the unity of the church. The 2008 Week of Prayer for Christian Unity was celebrated as the centennial. For the 2012 Week, the biblical text 1 Corinthians 15:51 was chosen with the theme "We will all be changed". The 2016 Week is provided by the Churches of Latvia and the theme is that all Christians are 'Called to proclaim the mighty acts of the Lord'. Week of Prayer for