Currently only Date properties allow searching ranges
in the web interface. This should be implemented for
numbers, too, e.g., that searching for 
1-200 (or similar syntax, see below)
for a number property will find values in the
(inclusive) range 1-200. A similar syntax for exclusive
ranges would be nice -- maybe use the mathematical
notation with an outward-facing angular bracket for an
exclusive range, e.g. 
[1,200] would find 1<=x<=200
]1,200[ would find 1<x<200
[1,200[ would find 1<=x<200
support for a list of several ranges in a single query
would be fine :-)
leaving out either the left or the right range number
should denote -infinity vs +infinity, respectively.

I currently have a requirement where searching for
numbers greater 0 would be very nice to have...