How to multiply Roman numerals? How to multiply Roman numerals? I need an algorithm of multiplication of numbers written in Roman numbers. Help me please. 

I don't like any on-line solutions to Numeral multiplication so I made one up.
The only thing you need to remember when multiplying is V x V = XXV all other multiple combinations are column shifts
Example: XXVII multiplied by XVIII
XXXVII across the top is multiplied by each individual numeral of XVIII down the left column, then each column is totalled.
$$
    \begin{matrix}
    &&&& XXX & V & II \\
    X && CCC & L & XX \\
    V &&& LLL & XX & V \\
     &&&&& VV \\
    I &&&& XXX & V & II \\
    I &&&& XXX & V & II \\
    I &&&& XXX & V & II \\
    ---- & ---- & ---- & ---- & ---- & ---- & ---- \\
    Carry & D & CCC & LLL & XXX & V \\
    : & = & = & = & = & = & = \\
    Total & D & C & L & X & V & I \\
    \end{matrix}
$$
E.g.   V (left) x II (top) = VV, carried to V column  VxV = XXV  and VxXXX = LLL
There are 6 I's which total VI the V is carried.
6 V's+that V carry = V + XXX carried
I have resisted the urge to use decimals to convert numerals at each stage, that's your task.
The final result is DCLXVI, a single occurrence of all numerals below M
A revalation perhaps?
All this only takes seconds on an Abacus and my division method is equally different
