Quick mental calculation vs ZX81

Game to enter within a certain period of time the answer of mental arithmetic calculations will appear on the exam. Many times in a row you can do correct? It is a challenge to the rankings!

Welcome to a taste of early 1980s home computing. This app focuses on the Sinclair ZX81 experience and is loaded with example software. A streamlined watchOS app is included, offering saved session syncing with the iOS app on the paired iPhone. Background: In 1980 the British company Science of Cambridge (later renamed Sinclair Research) released the Sinclair ZX80 home computer. The computer was developed with another technology company, Nine Tiles, and manufactured in a Timex Corporation factory in Dundee, Scotland. Followed in March 1981 by the even more popular successor, the Sinclair ZX81, both models had a profound impact on home and hobbyist computing in the UK and many other countries. Timex Corporation and Sinclair Research continued their joint venture and released the Timex Sinclair 1000 (TS1000) and 1500 (TS1500) variants of the ZX81 for the US market in July 1982 and July 1983 respectively. Meanwhile, another iconic British home computer, the Sinclair ZX Spectrum, was under development and hit the market in April 1982... but that's another story. Special thanks to Nine Tiles for granting permission to include the ROM code, to which they retain the intellectual property rights after all these years. Additionally, many thanks to all the developers of the loaded ZX81 software who have all granted permission to include their titles in the app. We hope this list of software will continue to grow in future updates.