(XXV) or XXV but with an horizontal line above the numerals XXV to indicate multiplication by a thousand.
Numerals in brackets also indicate multiplication by a thousand.
So: 25*1000 = 25000
XXV with a bar over all of it
It is 25000*(25000+1)/2 = 312,512,500
Roman numerals are a system for writing numbers, not words. the Roman numeral for 4 is IV.
XCVIII is 98 in Roman numerals
Roman numerals for 201 = CCI
1008 in Roman numberals is MVIII
DXXVII is the answer.
MMX
II
LXXV
MCCXXVIII
MDCCCXIX