“can can”

Fun fact: If you have a scientific calculator (literal or app) but no other conversion tool available, the conversion factor between miles and kilometres is almost exactly ln 5. Disturbingly close in fact.

That’s fewer keypresses than generating the Golden ratio or working out Fibonacci numbers. But if all you have is your head then, yeah, the Fibonacci trick is good enough in a pinch.

There are many such ways to memorize conversion ratios. Admittedly, this one is particularly cool, since you can construct it from the fairly trivial fibonacci series. But I still feel, it’s no replacement for the actual solution; get rid of imperial and adopt metric.