Fractional calculator
OwnerJames T. Hughinsinventor
Life of this patent
Estimating the term…
Abstract
A fractional calculator (10) has a keyboard (12) with numeral keys (18) and denominator keys (20). Through use of the numeral keys (18) and the denominator keys (20), fractional inputs may be entered into the calculator and calculations carried out on the inputs through use of function keys (22). A decimal/U.S. toggle key (26) allows the calculator to be used in either a conventional decimal mode or a fractional mode. When the calculator is used in a fractional mode, key (30) is used to differentiate between integers and numerators of fractions entered by means of the numeral keys (18). Key (28) may be used to distinguish between feet and inches in mixed unit entries during fractional mode operation. Display (14) includes indicators (38, 39, 40, 42, 44) for different modes of operation and different types of entries.
Claims10
A calculator for fractions, which comprises a keyboard including a plurality of number keys, a plurality of denominator keys having a preselected range of numbers, a plurality of function keys for selecting operations to be performed on whole numbers and fractions selected by actuation of said number keys for the whole numbers followed by actuation of a numerator function key in combination with said number keys for the numerator of the fraction and then selecting one of said preselected denominator numbers from said denominator keys, a display for showing entry of the selected numbers and fractions and results of the selected operations, and circuit means operatively connected to said keyboard and said display for carrying out the selected operations on the selected numbers and fractions, and for displaying the selected numbers, the selected operation, and the results of the selected operation on said display.
Dependencies are inferred from the claim text.