Abstract: A scientific calculator includes a conversion table memory for storing as a conversion table a combination of each kind of conversion equation and a selection number, a key board providing numeric keys and a specific key, a numeric value memory for storing the entered numeric values, a mode setting section for setting the current mode to a conversion mode, a designating section for designating the selection number during conversion mode, reading section for reading from the conversion table the conversion equation corresponding to the designated selection number, a conversion section for converting the numeric value stored in the numeric value memory from one unit to another on the basis of the read conversion equation, and a display section for displaying the converted numeric value.

Abstract: An electronic computer of the invention adopts prefix unary operators, so that key operation for entering arithmetic or mathematical expressions is performed in the normal order of the operands and operators of the expression, and moreover the last calculation result can be directly used as the operand for the prefix unary operator. Therefore, sequential calculations can be performed step by step while checking the intermediate results by simple key operation.

Abstract: An electronic apparatus provided with a device of calculating complex numbers includes a keyboard for entering calculation data including a value and an imaginary number unit i, an LCD device for displaying a result of performed calculation of the complex numbers consisting of a real number and an imaginary number unit i, and a processing unit.

Abstract: A portable electronic computer for conducting fraction calculations has a display including a first multiple-digit display area for displaying the numerator of a fraction, and a second multiple-digit display area for displaying the denominator of the fraction. The numbers of digits of the numerator and denominator of a fraction to be displayed are obtained. The number of digits of the numerator is compared with the number of digits of the denominator. The difference between the number of digits of the numerator and the number of digits of the denominator is calculated. When the number of digits of the numerator is smaller than the number of digits of the denominator, the numerator is displayed on the first display area with its position shifted to an upper digit place according to the difference.

Abstract: A multi-functional electronic desk calculator has numeral value keys for inputting a numeral value and a decimal point key for inputting a decimal point. The calculator also has a device for detecting depression of the numeral value keys to produce a first signal representative of being in a numeral value inputting mode, a device for detecting depression of the decimal point key to produce a second signal representative of input of the decimal point, a predetermined single key, and a device for operating the predetermined single key as a key used for inputting hexagesimal number when the first signal is produced and the second signal is not produced, and for operating the predetermined single key as a conversion key for performing conversion from decimal number to hexagesimal number when the first signal is not produced or when the second signal is produced.

Abstract: The desk-top calculator in accordance with the present invention comprises a constant access key, a ROM and a control unit. The ROM is arranged such that different types of constants are anteriorly stored therein and the constants are accessed through the operation of the constant access key. The control unit is arranged such that, as well as accessing successively the different types of constants stored in the ROM each time the constant access key is operated consecutively, after one of the contants is accessed through the operation of the constant access key, when another key is operated and the constant access key operated again thereafter, the control unit accesses the constant previously accessed in the first place.According to the arrangement described above, the operation of such a desk-top calculator is simplified and its operation efficiency is sharply improved.