Datexx has revolutionized the way you calculate with our innovative 2-Line TrackBack Calculators by remembering your entries for you, eliminating any ambiguities and worries. It's simple. Just keep going with your calculations and take advantage of its verification and correction functionalities, without having to start any calculations over. The 2-line LCD display clearly shows exactly what you entered on the top line, and provides the results on the bottom line, so you can be sure of your numbers. TrackBack up to 79 entries as you would in a journal.