The Fibonacci sequence is a series of numbers where every new number is the sum of the two previous ones in the series.
1, 1, 2, 3, 5, 8, 13, 21, etc.
The next number would be 13 + 21 = 34.
Here’s the thing: 5 mi = 8 km. 8 mi = 13 km. 13 mi = 21 km, and so on.
This works because the Fibonacci sequence increases following the golden ratio (1:1.618). The ratio between miles and km is 1:1.609, or very, very close to the golden ratio. Hence, the Fibonacci sequence provides very good approximations when converting between km and miles.