come si fa 10000 x 99999 ?

0 0 0 0 1 9 9 9 9 9 x = 0 0 0 0 9 0 0 0 0 9 0 0 0 0 9 0 0 0 0 9 0 0 0 0 9 0 0 0 0 9 9 9 9 9
x