I am in my 2nd year teaching math and have this question/concern. A significant portion of time each day (not taken from teaching time) is spent helping kids "troubleshoot" incorrect answers. It seems there are a great deal of errors invovling calculator use. each brand is slightly different and requires different keystrokes/input.I am unfamiliar with many of them and 90% of what we do I can calculate in my head anyway so I rarely use one. When I ask the kids about the operating instructions, they give me a blank look. They lean on these things but don't bother to understand how they work.It's frustrating for the student and for myself. Do you consider teaching the use of calculator as part of your standards or curriculum? BYW, I graduated HS in '76 so no one had a calculator at my school. I only acquired one in engineering school (a $100 TI that had the same capacity as a $2 calculator today.) If you do, how do you master the variety of different ones? Thanks for any input.