The core believes are what the company stands for, what its values are and want it wants to achieve. So you might say your customer is the most important asset and excellent customer service is key.
The operating believes are what people do everyday. They might think it is more important to them to get on with their tasks or go home on time rather than help a customer and go the extra mile.
One quick way to find out is to shop your own company and see what treatment you get as a customer.
In my experience is the incongruence of core and operating believes often one of the challenges that companies face in reaching their strategic goals and achieving growth.