Question 1188402
<br><pre>
# of 0's at the end of 60!
  60/5 = 12
  12/5 =  2
 -----------
         14

# of 0's at the end of 50!
  50/5 = 10
  10/5 =  2
 -----------
         12</pre>
There are 14 trailing 0's in 60! and only 12 in 50!, so 60!-50! has 12 trailing 0's.<br>
That means 60!-50!-1 has 12 trailing 9's.<br>
Using the pari calculator, available online: 60!-50!-1 = 8320987112741390113862247981509986337141564440296477108071636127449087 999 999 999 999<br>
which indeed has 12 trailing 9's<br>