Programmable calculator to use magnetic strips were the HP-41C and TI-59. Continuous memory does not lose its content when the calculator is switched off. With continuous memory the user can, for example, change batteries without losing the entered programs. Compact Cassettes offered a simple, inexpensive alternative to magnetic cards. Usually, an interface module, such as the Casio FA-1, was used to connect the calculator to an ordinary cassette recorder and digital data were encoded as frequency-shift keyed audio signals. Sharp and Hewlett-Packard also sold dedicated micro- or mini-cassette recorders that connected directly to the calculator. These set-ups, while being more practical and
QAMA Calculator 2016. QAMA Calculator The QAMA Calculator is a calculator that requires users to provide a reasonable estimate of the answer before the precise answer is delivered. QAMA stands for Quick Approximate Mental Arithmetic. Invented by Ilan Samson, it aims to get users to think first by estimating before they get the correct answer. Estimation is seen by many as an essential part of mathematics, and some believe that the presence and popularity of calculators could inhibit the use of estimation skills. A physical version of the calculator was released for sale in 2014, with apps for smartphones and tablets developed