come si fa 8547 x 12677 ?

7 4 5 8 7 7 6 2 1 x = 9 4 2 3 8 3 9 5 9 4 2 3 8 3 9 5 2 4 8 2 2 3 1 5 4 1 9 0 1 7 1 7 4 5 8 1 1 2 3 1 1 9 1 3 0 5 3 8 0 1
x