Network slicing is a key to supporting different quality-of-service requirements for users and application in the 5G network. However, allocating network slices efficiently while providing a minimum guaranteed level of service in a mobile core is challenging. To address this question, in our previous work we proposed an optimization model to allocate slices. It provided a static and manual allocation of slices. In this paper, we extend our work to dynamically allocated slices. We propose a dynamic slice allocation framework for the 5G core network. The proposed framework provides user-interaction to request slices and any required services that need to run on a slice(s). It can accept a single or multiple allocation requests, and it dynamically allocates them. Additionally, the framework allocates slices in a balanced fashion across available resources. We compare our framework with the First Come First Serve and First Available allocation scheme.