The current Jewish year is 5774 however it is popularly abbreviated as 774 - תשע״ד. I would like to know why this abbreviation was adopted. I realize that to write out the number 5,000 would require several letters; but then why stop at the hundreds column, why not just '74 - ע״ד instead?
I was told that the reason is that since there is no 'thousands' letter equivalent, we tend to show it as a separate indicator. It is similar to people who write the secular year as a two digit rather than a four digit number. Thus, the thousand indicator is shown as the letter with an apostrophe.