What the Cup ?! - How to get rid of subtraction (what's this 2-complement thing, anyway?)

After the presentation of Arthur Desuert on "Automate fabric making? A short introduction to Jacquard machines", the next session of "What the Cup ?!", will next Friday (12/09 at 16:00 P.M.) and will be untitled: "How to get rid of subtraction (what's this 2-complement thing, anyway?)". 

In this talk, Christophe (Deleuze) will speak about the 2-complement: "With (signed) integers, a-b is the same as a+(-b), suggesting every subtraction can be replaced by an addition.  But we were not taught to use that for practical calculations: it doesn't even seem to be possible to compute eg 123+(-42) other than by subtracting 42 from 123. However, computers use binary arithmetic and actually perform subtraction by adding the "2-complement". How does this work? What's the 2-complement, exactly?  Could we use something similar for our everyday, decimal, calculations?"

We hope to see you there !

Sincerely,

The "What the Cup ?!" organizing team.

PS: "What the Cup ?!" is the new format of talk at LCIS, and take place alongside the Coffee Break! This will be a chill event to talk about cultural topics, history, oddities, research tips & tricks, to complement all the science we do in the Speech Pizza. If you have an idea for a talk, feel free to contact us (Sebastien and/or Louis) !