The TI-83 is a popular graphing calculator for math and science. The TI-83 is enhanced with FLASH ROM memory that allows you to store Calculator Software Applications (Apps). The TI-83 family is 100% keystroke-for-keystroke compatible with the TI-84 Plus family. The step-up model is the TI-89 which adds significant symbollic algebraic manipulation. The TI-83 is permitted by the College Board and can be used tests such as the SAT. The TI-83 was first released in 1999 and currently sells for $100.