The “C” button’s function is vestigial. Back when calculators were commercialized, starting in the mid-1960s, their electronics were designed to operate as efficiently as possible.

People are just learning what the C, CE, and AC buttons on calculators mean as they share their shock after realising they all have different meanings and purposes which can make it easier to use ...

People have been baffled after 'finally' learning what the letter buttons C, CE, and AC stand for on a calculator and how to use them, with some people saying they've been curious for years ...

And because my fingers fly quickly, occasionally I'd hit the wrong number. Aaargh! Calculator lacks a backspace key, so my only option was to clear the entire entry and tap it out again. Right? Nope.

Amnesty's 'Panic Button' app will continue to be developed throughout the end of this year, and you can check out the status of the project and its uses around the world on their blog.

People have been baffled after 'finally' learning what the letter buttons C, CE, and AC stand for on a calculator and how to use them, with some people saying they've been curious for years ...