Round

Let's define r(x), (x > 0) like the number of the the least non-zero position in the decimal number, i. e.

r(12.1) = -1
r(2)    = 0
r(12)   = 0
r(10)   = 1

etc.

Given, b > a > 0, find all numbers in (a,b) where r() has its maxima .

(The point of the problem is to find "most rounded" numbers between a and b).