Question

calculati suma tuturor numerelor de doua cifre care dau rest 0 la impartirea cu 11

Answer 1

11 x 1 = 11
11 x 2 = 22
11 x 3 = 33
11 x 4 = 44
11 x 5 = 55
....
11 x 9 = 99

( 11 + 11x2 + 11x3 + ... + 11x9) = 11 x ( 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9)=
= 11 x 45 = 495