I've used the same TI-89 since I started my engineering coursework in 2004. It's a very useful piece of everyday kit for those of us who need to do basic algebr

I've used the same TI-89 since I started my engineering coursework in 2004. It's a very useful piece of everyday kit for those of us who need to do basic algebra and calculus on a day to day basis. In particular, I find it indespensible when just doing desktop brain work with pencil and paper. I'm sure using a smartphone would probably work just as well, but I like buttons. What bums me out is that there hasn't been any attempt to release a version that slims down the whole package, without revamping much of the actual capabilities of the device.