There are no hard and fast rules for table numbering, except that we must only use the table object numbers that we are licensed to use. If all we have is the basic table designer rights, we are generally allowed to create tables numbered from 50,000 to 50,009 (unless our license was defined differently compared to the typical one). If we need more table objects, we can purchase licensing for table objects numbered up to 99,999. Independent Software Vendors (ISVs) can purchase access to tables in other number ranges.
When creating several related tables, ideally, we should assign them to numbers in sequential order. We should let common sense be our guide for assigning table numbers. It requires considerable effort to renumber tables containing data.