| 摘要 |
An improved method and apparatus for performing operations on mathematical expressions in a data processing device, in which stored menus having labels of operations, performable on mathematical expressions, which are concordant with the syntax of individual expressions, are individually addressed by each expression developed in the data processing device. A selected label from a menu addressed by an expression is employed to perform an operation upon the expression. A change in form of an expression by a label of one menu, for example, selecting a subexpression of the expression, may address another menu. Where more than one menu exists for an expression a menu group is addressed by that expression and one menu of that group is displayed. The displayed menu and/or another menu or other menues from that group may be selected to provide labels for performing operations upon that expression.
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