I recently came across this page with some formulas for converting miles to kilometers. There is one that’s simple enough to do in your head:
Divide the number of miles by five and subtract that from the original. Then double the resulting number.
So I started by converting some of the speed limits from around town:
That’s when I noticed something interesting. When you add 5 to the miles per hour being converted, its metric equivalent goes up by 8. In other words, whenever a speed in miles per hour is a multiple of 5, its corresponding kilometers per hour will be a multiple of 8. Mind blowing or what. It’s then that a pattern begins to form and all of a sudden, understanding kilometers becomes less intimidating.
And so the pattern continues towards an easier way to understand the metric system.