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
Four-day week of work on Fridays. In 2016, a IT company in Romania, declared Monday as a day-off. As a result of reducing with 20% of working time, Friday has become much more productive. The employees said that three days off actually means 50% more free time then before. In New Zealand, trust company Perpetual Guardian announced in February 2018 that it would begin trialing a four-day work week in March 2018. Unlike many four-day week initiatives which require staff to work longer days for the same pay, or receive less pay, Perpetual Guardian’s plan, instigated by founder Andrew Barnes, saw the