Using numeric filters to create visualizations with our HubSpot data source is possible. All you need is a Workflow (in HubSpot) that translates the numerical value you care about into a word.

For example, if you have a score to qualify leads and you want to keep track of leads scoring 1000 or more, you can create a workflow like this in HubSpot (where a new "Lead score threshold met" is set to "Yes" when the score is 1000 or more):

Then, in Geckoboard, use the new "Lead score threshold met" as a filter, to can keep track of contacts meeting the score's threshold: