Computer system providing numeric calculations with less resource usage

A system comprising:

• one or more server computers communicatively connected to a data store, the one or more server computers comprising one or more processors and electronic digital memory storing one or more sequences of instructions which, when executed by the one or more processors, cause the one or more processors to perform:
• receiving, from a client computing device and at a computing system, a request to perform a digital numeric calculation by computer;
• identifying, based on the request, a plurality of stored digital data items that are needed to perform the calculation and retrieving the plurality of data items from a digital data store comprising one or more hard disk drives hosting a MapR JSON-based data store, the computer and data store comprising a multi-tenant system in which client data for different entities is stored together but subject to access control procedures;
• storing, in digital computer memory, the plurality of data items;
• generating a plurality of graphs for an in-memory calculation and storing the graphs in the digital computer memory, each graph of the plurality of graphs is for a particular entity among a plurality of different entities that are associated with tenants of a multi-tenant digital computer system, each of the graphs associated with a different user account, the graphs comprising a plurality of subsets, each of the subsets comprising two or more graphs for a particular entity, the user accounts corresponding to users who are employees of entities including the particular entity, wherein each graph of the plurality of graphs comprises one or more nodes, each node comprising executable program instructions to perform at least a portion of the calculation and at least one data item of the plurality of data items needed by the portion of the calculation, each edge of a graph representing a dependency of an associated node or nodes and guidance on an order of execution of nodes, the generating resulting in a digitally stored in-memory list of graphs;
• traversing the in-memory list and using a computer-implemented graph traversal algorithm and executing each of the plurality of graphs based on input from an in-memory context to generate a result value for the calculation that is stored in the in-memory context by traversing the graph and processing each node using the instructions of the node and the at least one data item of the node, including performing the executing without accessing the data store;
• the in-memory context including instructions or code to perform the calculation of the graph;
• storing, in the data store, the result value.