They could be Roman numerals that add up to 1000: DD = M
They mean 500+500 = DD or M because they are both equivalent to 1000
It is: DD = M and M*C = (C) which means 1,000*100 = 100,000
In mm/dd/yyyy format: V. XXIV. MMXII.
In dd/mm/yyyy format, it is XXVIII - V - MCMLXXXVI In mm/dd/yyyy format, it is V - XXVIII - MCMLXXXVI
They could be Roman numerals that add up to 1000: DD = M
They mean 500+500 = DD or M because they are both equivalent to 1000
It is: DD = M and M*C = (C) which means 1,000*100 = 100,000
In dd/mm/yyy format: I. X. MCMXCI.
In dd/mm/yyy format: X. XI. MCMLCCCV.
In mm/dd/yyyy format: V. XXIV. MMXII.
In dd/mm/yyyy format, it is XXVIII - V - MCMLXXXVI In mm/dd/yyyy format, it is V - XXVIII - MCMLXXXVI
I-VII-MMXI or VII-1-MMXI depending on which date format you use (DD-MM-YYYY or MM-DD-YYYY)
VI/V/MMVI (MM/DD/YYYY) or as people in England write V/VI/MMVI (DD/MM/YYYY)
99+1056 = 1155 or MCLV in Roman numerals Today we write out 99 in Roman numerals as XCIX but the Romans themselves would have probably wrote it out simply as IC (-1+100 = 99)
DDXCIX is not a real Roman numeral. D = 500 and DD if it existed would mean 500 + 500, which is 1000 but there is a Roman numeral for 1000, which is M, so the combination of DD would never be used. The numeral should be written as MXCIX and it represents 1099.
XIII (13)