Maths has a ton of fascinating quirks. For example, if you want to convert between miles and kilometres, you can use the Fibonacci sequence to make a conversion with a stunning degree of accuracy.

Photo by Chad Elliott.

The Fibonacci sequence, which is the basis for the golden ratio, goes like this:

`0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144`

Each number in the sequence after the first two is the sum of the previous two numbers. Coincidentally, it works as a nearly-accurate converter between miles and kilometres. Look at any number in the sequence as a number of miles and the next number in the sequence is approximately that same distance in kilometres. For example, 8km is about 13km. Thirteen miles is about the same as 21km.

As Reddit user daneah explains, this is because the golden ratio (~1.618) is very close to the conversion of miles to kilometres (~1.609). Of course, that tiny difference will break down eventually, but for everyday mental conversions, it's handy.

You can use Fibonacci sequence as quite accurate miles to kilometers conversion. [Reddit]

## Comments

Way quicker to divide multiply by 1.6... unless you're a freak who can memorise the sequence beyond 50-100... in which case you don't need this trick because you're probably smart ;)

A freak probably finds it difficult to memorise, jaded, is it?

The sequence is as easy to memorise as the phonetic alphabet, both taught when I went to school.

The sequence works in many other ways, spiral nautical snail shells, spiral staircases, petals on a flower, segments of a pineapple and pine cone, population of bees and thousands upon thousands of natural phenomina are based on the sequence, the Golden Ratio.

How is 8km equal to 13km?

Why would you even need to do this?

Are miles even a thing?

I'm planning a U.S. holiday so I'm assuming cars and speed signs will be in old school measurements, unless their cars have been upgraded.

Why memorise parts of the fibonacci sequence to convert speeds when you could just memorise the common speeds. Or even just deduce them.

60mph is 100kph so 30mph must be 50kmh.

A depressingly large portion of the population cant figure that if 60 mph = 100 kph then 30 mph = 50 kph...

Sadly its far more common than you think, I play tournament poker, and see it every day.

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