Abstract: In a calculator, apparatus and method for supplying a default denominator for entering and displaying fractions. A default value is selected and stored with a simple procedure and may be retrieved for combination with a numerator value to create a fraction by a single key stroke.

Abstract: In a calculating device, a method and apparatus for representing to a user the state of variables in multiple equations to be solved. The representation in the present embodiment is through a user interface. The interface displays labels assigned to the variables within the multiple equations and indicates to the user on the label the state of each variable. These states are four: user-supplied values (U); calculator-supplied values (C); related values (R); and non-related values (N). Related values (R) are values that were used or solved for together in the latest solution of the equations. Through menu keys assigned to the variables represented by the labels, a user can supply or clear values for the variables for the next solution. The method also includes saving the order in which the variables are found and the order in which the equations are solved. This information allows the user to review the solution path followed by the calculating device in solving the multiple equations.

Abstract: In a calculating device, a method for calculating a fraction that most accurately represents a related decimal value stored within the device. The user may select a maximum denominator value to limit the amount of calculation involved.

Abstract: In a calculating device, a method for indicating the round-off status of a fractional or decimal value displayed. This method includes receiving a numerical value, formatting the numerical value in either fractional or decimal form, and comparing the actual value with the formatted value. Thereafter, if the actual value is greater than the formatted value a "greater than" indicator is shown along with the formatted value, and if the actual value is less than the formatted value a "less than" indicator is shown along with the formatted value.

Abstract: In a calculating device, a method to allow a user to enter fractions in the form "b/c", where "b" and "c" are integers; "b/c" is a fraction; and the denominator "c" is within a prespecified range. The method to enter real number fractions includes activating one or more digit keys and the successive pressing of a primary function key to distinguish the previously entered numerator value from a subsequently entered denominator value.