aa (in baza 10) inseamna 10a + a = 11a;
Analog, bb inseamna 11b;
aaa (in baza 10) inseamna 100a+ 10a + a = 111a;
Analog, bbb inseamna 111b;
Avem asa in exercitiul tau: [(99 + 111 + 11) x 3 -111] x 11 =
(221 x 3 - 111) x 11 = (663 - 111) x 11 = 552 x 11 = 6072.