Thanks, Jay.
I don’t know if that’s really the best solution, but it feels like would mimic the way it worked before.
I’d also be perfectly happy with a pass by reference, so that there’s only one calculator model shared between the two, and as you go back and forth between the pages they stay in sync with each other.
Once again, I don’t know enough of the architecture to tell if that’s possible, but it seems like it might be an option.