Because immx = mmviiii. If we place i to both sides of mviiii we have immviiiii which when simplified becomes immx (2010 minus 1). Reverse this procedure to immx and we go back to mmviiii (2009).
If you consider the numbers:
1 2 3 4 5 6 7 8 9 10, in roman numerals
I II III IV V VI VII VIII IX X, respectively
you can see the the number 9 in similar to 4 in that the 'I' is placed before the major number, in these cases 'V' and 'X' for 5 and 10, so the number 9 would be 10 (X) minus 1 (I) so number 9 would be IX.
February II MMVIIII or II-II-IMMX. Note that 2009 in Roman numerals is not MMIX.
i xx mmviiii or i xx immx
XXIII-II-MMVIIII or XXIII-II-IMMX and notXXIII-II-MMIX
In today's terms the conversion is: January-XIII-MMIX But in the times of the Romans themselves they probably wrote out the number 2009 as MMVIIII which can be simplified to IMMX
In today's terms 6-27-2009 expressed in Roman numerals is VI-XXVII-MMIX. However, the Romans themselves would have probably wrote out the number 2009 as MMVIIII which can be simplified to IMMX.
VIIII XXVIII MMVIIII or IX IIXXX IMMX.
February II MMVIIII or II-II-IMMX. Note that 2009 in Roman numerals is not MMIX.
i xx mmviiii or i xx immx
XXIII-II-MMVIIII or XXIII-II-IMMX and notXXIII-II-MMIX
In today's terms the conversion is: January-XIII-MMIX But in the times of the Romans themselves they probably wrote out the number 2009 as MMVIIII which can be simplified to IMMX
In today's terms 6-27-2009 expressed in Roman numerals is VI-XXVII-MMIX. However, the Romans themselves would have probably wrote out the number 2009 as MMVIIII which can be simplified to IMMX.
In today's terms it is: December-XXVI-MMIX or as XII-XXVI-MMIX But in times past the Romans themselves would have probably wrote out the number 2009 as MMVIIII which can be simplified to IMMX
In today's terms it is: V-XII-MMIX However, the Romans themselves would have probably written out the number 2009 as MMVIIII which can be simplified to IMMX in the same way that the Roman numerals IIII and VIIII (4 and 9) are simplified to IV and IX respectively.
In today's modern notation it is: XXVI-XII-MMIX However, the Romans themselves would have probably wrote out the number 2009 as MMVIIII which can be simplified to IMMX in the same way that the Roman numerals IIII and VIIII (4 and 9) are simplified to IV and IX respectively.
April XVII MMVIIII or April XVII IMMX. Take note that 2009 is not MMIX in Roman numerals. Conventionally accept wisdom tells us that MMIX (2000 + 9) and MMVIIII(200 + 5 + 4) both mean 2009, although the former is more popular as it is shorter. The alternative mentioned above, IMMV is incorrect on two counts. According to the website Algebra.com Roman numerals read from left to right and always start with the highest value numeral, as I (1) is patently less than M (1000) IMMX is clearly wrong. Also while I may preceed V or X it should not be placed in front of any higher value numerals.
In today's terms, it is: XII-X-MMIX However, the Romans themselves would have probably written out the number 2009 as MMVIIII which can be simplified to IMMX in the same way that the Roman numerals IIII and VIIII (4 and 9) are simplified to IV and IX respectively.
In today's terms it is: VI-XXVI-MMIX But the Romans themselves would have probably calculated 2009 as MMVIIII and simply wrote it out as IMMX (-1+2010 = 2009)