Electronic calculators became the must have gadget of the mid-1970s. Initially featuring LED (light emitting display) technology, by the early 1980s screens moved to the familiar black against grey, LCD displays. The dominant company in the worldwide calculator scene was Casio, and with literally 100s of models flooding the market, it wasn’t long before manufacturers were adding games and other strange additional functions to make their calculator stand out from the crowd. In recent years Electronic Calculatorshave become highly collectible, with some rare models fetching four figure sums