Texas Instruments TI-92 Plus Graphing Calculator Over 500 KB memory for storing functions, programs, and data Pretty Print technology displays mathematical expressions as they appear in textbooks QWERTY keyboard and large display; real-time rotation of 3-D surfaces Electronically upgradable using flash technology Input/output port and cable; also supports optional TI-GRAPH LINK. The screen is black because the brightness needs to be turned up. This happens when there are no batteries inside them. Please press the second button and the arrow up or down. Please repaet this until the desired brightness is achieved