I have recently been informed that the ancient Jewish calendar does not count the year at the beginning of a century: no zero year. So for example 1999- 2001 is one year not two. This can be important when one tries to calculate specific dates in prophesy to determine accuracy. Are there any expert explanations that a member could share on this?
Since the year begins at Rosh Hashanah, the number of the year changes then. Thus the year spans the secular year which changes in January. Thus this year (5776) started at Rosh Hashana 2015 and will end Rosh Hashanah 2016. The year 5700 was from Rosh Hashanah 1939 to Rosh Hashanah 1940. You may have heard about "year 0" of creation which is a virtual year. There is a discussion as to whether Adam was created at the beginning of year 1 which would make the previous five days of creation "year 0" (a virtual year) or if those five "days" were year 1 and Adam was created at the beginning of "year 2".