This is right. This requires a discussion a bit wider than 420 letters, even more when they come from Rowling

Km is 10³m cm is 10^-2m so the difference is 10⁵ i.e. 100000 (one with 5 zeroes)

Or more intuitively one centi-meter is a 1/100 of a meter and Kilo-Meter is 1000 meter therefore 100*1000 100000

It is quite intuitive, once you start using it

What’s weird is why we don’t use Megameters and megagrams (i.e. one metric ton)

If only there was a solution, I don’t know, a cable resistent to jamming the ether, something we could call ether-jamming-resistant-network, in short Ethernet

I know… I am just dreaming :-P