Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Very handy calculator.

I originally hated it... if only for the way it looked. But the appearance grew on me, and the calculator itself was a joy to use. I strongly prefer RPN (reverse Polish notation mode of data entry and execution), which is the input system for this calculator. It may not have the massive memory of a graphing calculator, but there is more than enough memory for many short or "medium" length (whatever that means) programs. It comes with a constants library and you can create your own equation library. It is lightweight and for general use, more than fast enough. If you want to converge some series, maybe, it may take all night or so, but otherwise, a very pleasurable calculator to use. I reach for it more than any other one I have (and there a few in the drawer). Battery life, for me, seems fairlly long, many months, more than a year on two CR 2025 button cells.