come si fa 999 x 999999 ?

9 9 9 9 9 9 9 9 9 x = 1 8 9 8 9 8 1 8 9 8 9 8 1 8 9 8 9 8 1 8 9 8 9 8 1 8 9 8 9 8 1 8 9 8 9 8 1 1 2 2 2 2 1 1 0 0 9 9 9 8 9 9
x