Patent ID: 7882163
Filing Date: 2011-02-01
Classification: G06F

Abstract:
1. An electronic abacus, comprising: an calculating apparatus, an input apparatus, and a display apparatus, the input apparatus and the display apparatus connected with the calculating apparatus, the calculating apparatus processing input information from the input apparatus, and displaying processed input information on the display apparatus, the input apparatus comprising function keys and number input keys, the number input keys comprising a plurality of sets of numeral keys, each set of numeral keys corresponding to one digit of input information displayed on the display apparatus, and each set of the numeral keys comprising keys indicating “5”, “−5”, “4”, “−4”, “3”, “−3”, “2”, “−2”, “1”, and “−1”; and wherein negative numbers are derived from direct input from numeral keys “−5”, “−4”, “−3”, “−2”, and “−1”, wherein a negative number inputs result in an auto subtraction operation.