Worst calculator I've ever purchased. If I hadn't already thrown out the box (since when is a calculator bad?) I would return it. Some keys have to be pressed extra hard to get them to register, like the number 9, others if you press too hard register double. This means I have to watch every item entered to make sure it is correct, when normally my fingers can fly over a number pad. I end up running tapes several times to make sure I get a good total. Very unr..