Olympiad Test: Roman Numerals -2

The correct answer is b

Because 

718- 19= 709

So in Roman numerals it will be VIDCXCIII

we should always use the DMAS rule whenever we are adding or subtracting Roman numerals.

1516 =
1000+500+10+5+1 =
M+D+X+V+I =
MDXVI

630 =
500+100+10+10+10 =
D+C+X+X+X =
DCXXX

We have
DCCCXXX = 500 + 100 + 100 + 100
+ 10 + 10 + 10 = 830

737 =
500+100+100+10+10+10+5+1+1 =
D+C+C+X+X+X+V+I+I =
DCCXXXVII

2676 =
1000+1000+500+100+50+10+10+5+1 =
M+M+D+C+L+X+X+V+I =
MMDCLXXVI

2990 =
1000+1000+(1000-100)+(100-10) =
M+M+(M-C)+(C-X) =
M+M+CM+XC =
MMCMXC

Here 5 × 4 = V × IV
and 5 × 4 = 20 = XX

We have XII – II = 12 – 2 = 10 = X

We have DVI – XXIV = 500 + 6 – 14
= 506 – 24
and CDL XXX II
= (500 – 100) + 50 + 10 + 10 + 10 + 2
= 482