1. numero -> centena decena unidad
centena -> C R1 | D | ℇ
R1 -> D | R2 | C R2
R2 -> C | ℇ
decenaMenor -> decenaMenor X | ℇ
decenaMenor ->X R3 | R4 decenaMenor
R3 -> X R3 | R4 decenaMenor
R3 -> L | C

2. R4 -> ℇ | L
unidad -> R5 unidadMenor | I R6
R5 -> ℇ | V
R6 -> V | X
unidadMenor -> unidadMenor I | ℇ