As other tablet-makers concentrate on Android or Windows, HP covers all the bases with both. Looking like nonidentical twiins, HP’s SlateBook x2 (photo, right) uses the latest Android software, while its larger Split x2 sibling (photo, left) relies on Windows so your school won’t have to buy any new software. Based on Android 4.2 (aka JellyBean) the $480 SlateBook x2 performs on its own or with its snap-on keyboard. The secret is that both units have batteries, so that the combined system has a full-day machine. Inside is NVidia’s Tegra 4 processor, a 10.1-inch touch-screen and 64GB of storage. By contrast, the Split x2 uses Windows 8 and a Core i processor, creating a system that is just as convenient as an Ultrabook or as a tablet. It has a 13.3-inch touch-display. It costs $800, but has the distinct advantage of letting schools continue to use the software they have, know how to use and have paid for.