abc = 100a + 10b + c
bca = 100b + 10c + a
cab = 100c + 10a + b
(abc + bca + cab) / (a+b+c) =
(100a+10b+c + 100b + 10c + a + 100c + 10a + b) / (a+b+c)
grupezi a b c impreuna
(100a + 10a + a + 100b + 10b + b + 100c +10c + c) / (a + b +c)
(111a + 111b + 111c) / (a + b + c)
dai factor comun
111(a+ b + c)/(a+b+c)
= 111
