Răspuns :
ABC + BCA +CAB l 111
100A + 10B + C + 100B + 10C +A + 100C + 10A + B l 111
111A + 111B + 111C l 111
111 ( A + B + C ) l 111
ABC + BCA +CAB l 111
100A + 10B + C + 100B + 10C +A + 100C + 10A + B l 111
111A + 111B + 111C l 111
111 ( A + B + C ) l 111