Solution
We start with
1/8:.12500000.
Think of this as: .125 _ _ _ _ _ , where there are 10 possible digits for each blank, thus 105 possible 8-place decimal numbers greater than 81 and beginning with .125. There is a similar result for .126 _ _ _ _ _, and for .127 _ _ _ _ _, and so on up to .129 _ _ _ _ _. This makes 5⋅105 numbers so far.
Next, for .13 _ _ _ _ _ _, .14 _ _ _ _ _ _, and so on up to .19 _ _ _ _ _ _, we get 7⋅106 more. And for .2 _ _ _ _ _ _ _, .3 _ _ _ _ _ _ _, and .4 _ _ _ _ _ _ _, we get 3⋅107 more.
Finally, there is .5 itself, i.e., 21. One possibility.
Now add:
(5⋅105)+(7⋅106)+(3⋅107)+1=37,500,001.
That's a lot!