Everyday utilities5 resources

G

GeoGebra is a mathematics online tool, available on Linux: statistics and charts, real-time collaboration.

QM

Free QR code generator with logo, colours and high-resolution export.

Internet Archive service to browse past versions of web pages and save a page for posterity.

Computational knowledge engine: maths, units, science and data answered in plain language; step-by-step solutions are paid.

Hundreds of solvers for ciphers, codes, maths and puzzles (Caesar, Vigenère, Morse, anagrams…), funded by advertising.