<P> A week is a time unit equal to seven days . It is the standard time period used for cycles of rest days in most parts of the world, mostly alongside--although not strictly part of--the Gregorian calendar . </P> <P> The days of the week were named after the classical planets (derived from the astrological system of planetary hours) in the Roman era . In English, the names are Monday, Tuesday, Wednesday, Thursday, Friday, Saturday and Sunday . </P>

1 week is equal to how many days