Abstract: A computer spreadsheet application program on a graphing calculator or other computer that allows the user to calculate and enter results inside a spreadsheet cell without using or entering a formula. Similarly, other embodiments include the same user interface functionality in a ROM software application package that is executed on a graphing calculator or other handheld device.

Abstract: A graphing calculator (10) or other computer based teaching tool that displays inequalities on a display screen. In contrast to prior art devices, the present invention provides displays of inequalities that are mathematically correct and consistent with non-electronic display of inequalities such as textbooks and black board representations to reinforce traditional teaching methods and help the student or user to readily see and understand the mathematical concepts involved. The display methods of the present invention are particularly useful for small, low-resolution displays that are typical of handheld computers and calculators.

Abstract: A graphing calculator (10) having an X=Editor with inequalities. The calculator (10) is programmed to provide an X=Editor which displays one or more “X=” to allow input of a vertical line inequality. The X=Editor allows the user to input an inequality symbol and a constant for each X, allows the user to select or deselect each X, and a graph function to graph each selected X on the X=Editor display.

Abstract: A graphing calculator (10) or other computer based teaching tool having an X=Editor with equations and inequalities. The calculator (10) is programmed to provide an X=Editor which displays one or more “X=” to allow input of a vertical line equation or inequality. The X=Editor allows the user to input a relational symbol and a constant for each X, allows the user to select or deselect each X, and a graph function to graph each selected X on the X=Editor display.