Using subscripts now we have 11 different letters
and there are ways to rearrange those.
In any of those rearrangements, how many ways can we leave the I’s fixed but rearrange their subscripts?
Well it is . Rright?
So if we drop the subscripts on the I's we would have to divide by .
The same idea for any repeated letter. So the number of ways to rearrange the letters is
Do you see this much?