Question 1104768
I think Alan3354's answer does not account for the cases where the identical digits are separated by  one or two of the other two digits (i.e. the 4 identical digits do not behave exactly like a single digit).  

I had 10800 written in my notebook but I hadn't worked out the problem for the case where you pick the 2 not-necessarily-identical digits first, so seeing 'greenstamps' solution reminded me to try it:

If one picks the 2 not-necessarily-identical digits first:  C(10,2) = 45 ways
Then the 4 identical digits can be picked in C(8,1) = 8 ways
And the arrangements are 6!/4! = 30 ways

45*8*30 = 10800  which agrees with the selection done the other way (greenstamps answer)