How to get a number of form submissions within a date range.


I'm looking to put together a dashboard and on it I would like to display a number. We collect work requests via form fills. Each form fill creates a line in my sheet. And I would like to be able to report things like 'how many form fills did we get last quarter'. I know I can filter my sheet to show just the rows that were created within a date range, then count them up. But what can I use to tell me that number automatically?