I use π/2
Relevant xk: https://xkcd.com/1047/
A mathematician's way of converting miles to kilometers
31–40 of 208 posts
Re: A mathematician's way of converting miles to kilometers
#32[deleted]
Re: A mathematician's way of converting miles to kilometers
#33It's both easier and more accurate to multiply by 1.6
Not if you just remember 3,5,8,13 . You do not need to remember all fibonacci numbers, just the above and rest you can multiple by 2,5,10 and get them
Re: A mathematician's way of converting miles to kilometers
#34Re: A mathematician's way of converting miles to kilometers
#35My way: x1.5 for speed limits, x2 for hikes.
ahah
Re: A mathematician's way of converting miles to kilometers
#36it's good for a gag - but it's much simpler to just go and add half of the number + a tenth to convert from miles to kms
Re: A mathematician's way of converting miles to kilometers
#37The pendulum has now swung the other way on the misconception by the general public of mathematicians being great at mental arithmetic, and it's become a meme for some mathematicians to take some pride in being average or poor at mental arithmetic. In my experience, most mathematicians (or anyone working in a quantitative field) don't have issues quickly approximating 1.6 * X.
Anybody who's taken CS 101 can estimate 1.6 * n too since they spend half the year in base2 or base16. It's 1 (n) + 6 (n)/10 since we're using base 10. For example, 5mi to ~8km: 1 (5) + 6 (5)/10 = 5 + 30/10 or 5 + 3.
That's how I was taught to do it in primary school, yes it's simple, but I don't see what bases 2 or 16 have to do with it?
Re: A mathematician's way of converting miles to kilometers
#38An engineer's way: Pi = 3
Re: A mathematician's way of converting miles to kilometers
#39Earlier quoted context omitted.
Not if you just remember 3,5,8,13 . You do not need to remember all fibonacci numbers, just the above and rest you can multiple by 2,5,10 and get them
How many km is 4 miles? That's not on the list of numbers.
4 is the average of 3 and 5, so its km value is the average of 5 and 8 (assuming the Fibonacci series to be a geometric progression as described in the tweet).
While I can do this for 4km, I can't for different values like 9km. I've done the multiply-by-1.6 thing often enough by now to be fast enough at it, so I'll likely be sticking to it. This is a cool trick nevertheless.
Re: A mathematician's way of converting miles to kilometers
#40Wait, doesn’t everyone know there 1.6 times tables ?