How does this speed calculation work?

[CNBA3]

So I was looking at these blogs about calculating speeds from difference perspectives, I found it interesting, but how exactly does it work when you type them down on the computer to get a result? is it ratio calculator?

here is an example with the blogs in reference:

c*5:0,001= 5000 c MFTL+

Seeing lasers as frozen

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Ren gotta go fast

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