The Quick Gadgets “Quick Issue Statistics” and “Quick Two Dimensional Filter Statistics” have advanced functionality which is not available in the Atlassian gadgets, besides being interactive.

Per default the gadgets aggregate the number of issues. In the gadget settings you can edit the “Values shown” to any Jira number field, e.g. Original Estimate. Changing that you can aggregate e.g. the Original Estimate of all issues which are displayed in the gadget.