Question

Determinati ultima cifra a numerelor 13^74; 99^51; 11^53+15^5+17^53; 313^100; 68^86; 89^37+88^38+87^39

Answer 1

Uc(13^74) = Uc(13^72 ·13²) = Uc(13²) = 9 Uc(99^51) = 9 Uc(9^1,3,5,7....51) =9 Uc[11^53 + 53^53 + 17^53] = Uc(1 + 3 + 7) = Uc(11) = 1 Uc(313^100) = Uc(3^4·25) = 1 Uc(68^86 )=Uc( 68^84 ,68²) = 4 Uc(89^37 + 88^38 + 87^39) = Uc( 9 + 4 + 3) = Uc(16) = 6 Uc(71^10000001) = 1 Uc(1009^9001) = 9 Uc(77^36 + 77^37 + 77^38 + 77^39) = Uc(1+7+9 +3) = Uc(20) = 0 Sper ca te-am ajutat !! Bafta !!