come si fa 9999 x 9999 ?

9 9 9 9 9 9 9 9 x = 1 8 9 8 9 8 9 8 1 8 9 8 9 8 9 8 1 8 9 8 9 8 9 8 1 8 9 8 9 8 9 8 1 1 2 3 2 1 1 0 0 0 8 9 9 9
x