Have you ever wondered what calculations Excel Solver does to discover your model? Be curious no longer; this spreadsheet (ObserveCalculations.xlsm) will show you exactly what goes on. Be sure to bring up the VBA Immediate window (Alt-F11) to watch the calculations in real time. To make it easier, we’ve also copied some of this output into the sheets. You can, of course, also use this to watch OpenSolver doing its work. Enjoy. PS: You’ll see that things have changed quite a bit between Solver 2007 and Solver 2010…