This article is within the scope of WikiProject Years, a collaborative effort to improve the coverage of Years on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.YearsWikipedia:WikiProject YearsTemplate:WikiProject YearsYears articles
This article is within the scope of WikiProject Lists, an attempt to structure and organize all list pages on Wikipedia. If you wish to help, please visit the project page, where you can join the project and/or contribute to the discussion.ListsWikipedia:WikiProject ListsTemplate:WikiProject ListsList articles
This article is within the scope of WikiProject History, a collaborative effort to improve the coverage of the subject of History on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.HistoryWikipedia:WikiProject HistoryTemplate:WikiProject Historyhistory articles
Well, decades are usually referred to as "the 1920s", "the 1870s" etc. To fit into that scheme, we need decades that start (or end, in the BC case) with a year ending in zero. (This means that the first "decades" AD and BC have only nine years - see 0s and 0s BC.)
