A method of input and evaluation of fractions using a calculator is described. The calculator receives a user-entered expression including a fraction where the fraction is entered using a division key. The user-entered expression causes the calculator to evaluate the user-entered expression and display...http://www.google.com.tw/patents/US7325020?utm_source=gb-gplus-share專利 US7325020 - Input and evaluation of fractions using a calculator
