It is not obvious to users that one can enhance searches using Google number range style. I had to find this information out through this meta question. Enhance the Advanced Search Tips to note the basic syntax for search by range; there is enough vertical space for it.
Relevant text paraphrased from Nick Craver's source answer in Advanced Search Tips style:
range: score:..2 (<= 2) score:-2.. (>= -2) score:-2..2 (>= -2 and <= 2) score:2..2 (2)