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:
mph | km/h |
40 | 64 |
45 | 72 |
65 | 104 |
70 | 112 |
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.
mph | km/h |
5 | 8 |
10 | 16 |
15 | 24 |
20 | 32 |
25 | 40 |
30 | 48 |
35 | 56 |
40 | 64 |
45 | 72 |
50 | 80 |
And so the pattern continues towards an easier way to understand the metric system.