| 摘要 |
A programmable electronic calculator for numerical evaluation of mathematical problems operates through the application of one or more basic mathematical operators, properly grouped, to each input numerical operand of a mathematical problem according to the accepted rules of mathematical combinations. One may select any numerical operand, any of the four basic arithmetic operators, left parenthesis and right parenthesis to denote groupings, a storage register for receiving a numerical operand to be used in computation or a numerical operand representing a result of a partial or final computation, or a storage register whose contents it is desired to print. Entry of each numerical operand and mathematical operator is accompanied by a printed record of that numerical operand and that mathematical operator so that the mathematical problem may be continually monitored as it is being entered. Depression of an equals key is followed by evaluation of previously designated operations and printing of the result. Selection of a left (or opening) parenthesis causes the contents of first and second accumulator registers in an arithmetic unit to shift to third and fourth accumulator registers in the arithmetic unit respectively. Selection of a right (or closing) parenthesis causes the shifting and combining of previously stored numerical operands to produce the result of the arithmetic combination embraced within a sequence denoted by a mating left parenthesis. One may select a learn mode in which steps are entered in a learn memory by working out a mathematical problem, each selected operation corresponding to a step in the learn memory. Thereafter, one may select an automatic computation mode to cause the operations previously stored in the learn memory to be carried out in sequence until a desired result is obtained or a predetermined point in the program stored in learn memory is reached.
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