come si fa 19999 x 99999 ?

9 9 9 9 1 9 9 9 9 9 x = 1 8 9 8 9 8 9 8 7 1 1 8 9 8 9 8 9 8 7 1 1 8 9 8 9 8 9 8 7 1 1 8 9 8 9 8 9 8 7 1 1 8 9 8 9 8 9 8 7 1 1 1 2 3 3 2 1 1 0 0 0 8 8 9 9 9
x