CD is the Roman numeral for 400.
400
CD
400 = CD
CD = 400
CD
497 = 400 + 90 + 7 = CDXCVII
Converting between Arabic and Roman Numbers we get,roman numeral CD in standard form is written as 400. CD=400.
The numeral XMCMV is not a Roman numeral as it does not follow te rules for wrting numerals. X (10) should never preceed any numeral of a higher value than C (100). If te numeral XMCMV did exist it might be supposed to have a value of XM (990) + CM = (900) + V (5) which would equal 1895 but the correct Roman numeral for 1895 is MDCCCXCV
((CD)) = 10*1000*400 = 4,000,000
it would equal 400 but it is the incorrect way of writing 400. the way of writing 400 is CD
The Roman numeral CDXC represents the number 490. C (100) is subtracted from D (500) to give 400, and XC (90) is added to 400 to get 490.