Pulling a number from the graph

This is a newbie CL question: I know how to put a number into the graph component using the math input.latex command. Now I’m wondering: Is it possible to pull a number OUT of the graph?

Example: Let’s say I want to define two variables, A and B, based on student input. Can I set up a third variable C = B - A within the calculator and then export the value to another component?

Yes. You can access that variable with something like this: