3 ms·

You might use them more if they were more convenient in your number system.

bhaak 9y ago
Maybe not. Case in point, our current time measurement system. We often talk about half an hour and a quarter of an hour. But almost never about a third of an hour or a fifth of an hour.
- comex 9y ago
  A third of an hour is 20 minutes, which we talk about all the time. We just don’t call it “third of an hour”…
  - bhaak 9y ago
    Yes but that's not in relation to the hour but in relation to the sub unit of minutes. How often do you talk about 20 minutes because you can neatly stuff 3 of those time periods in one hour?
    - ajuc 9y ago
      25 and 50 minutes are more natural than 20 minutes from decimal POV. How often do you talk about them vs 20 and 30 minutes? I'd say the fact that 15, 20 and 30 fit nicely into an hour plays a role in their popularity, even if you don't realize you use them for that reason.
      - Dylan16807 9y ago
        > 25 and 50 minutes are more natural than 20 minutes from decimal POV. Not really. Quarter hours and half hours are natural units. This is true no matter how many minutes we divide an hour into. There's nothing special about "25" when you're building up from 1. 25 is only special when you're splitting up 100, and nothing uses 100-minute blocks so that doesn't happen. > I'd say the fact that 15, 20 and 30 fit nicely into an hour plays a role in their popularity I'm skeptical for 20. I think 20 being a nice round number plays a much bigger factor here. If hours were 65 minutes I think you'd see just as much use of "20 minutes".
        ajuc 9y ago
        If 20 minutes was used because it's round, then we would expect 40 minutes to be used commonly. I'd say 45 minutes is used much more often. As for non-time-related units, I hear 25 deko more often than 20 deko when buying food. I don't think there's really a distinction between building up and down. When you're talking about 250 meters do you build up from meters or down from kilometers? I think both.
    - comex 9y ago
      > How often do you talk about 20 minutes because you can neatly stuff 3 of those time periods in one hour? Dunno. I personally 'visualize' 20 minutes as a third of an hour. I don't know how common it is to actually stuff an hour full of 20 minute periods, but it happens - you see a schedule with X:00, X:20, X:40. Multiples of 15 or 10 minutes do seem to be more common in that case. But it definitely matters to some extent that it's a divisor. Consider how rare 25 minutes is compared to 20 or 30. If you look at it only as a number of minutes, 25 seems a bit less 'round', but not too much; we often say "25 cents", after all. (And it's 5 squared and a quarter of 100.) But 25 minute periods are less convenient to calculate with, because adding them tends to result in odd/less consistent minute values, because it's not a divisor of 60.
mfukar 9y ago
I have a family of 6. I often divide a cake by 6. If my number system makes it more convenient to divide by 8, that doesn't really change my workload.
- jacobolus 9y ago
  Dividing by both 6 and 8 (also 2, 3, 4, 9, 12, 16, 18, ...) is easy in a duodecimal system. In a sexagesimal system it’s additionally easy to divide by 5, 10, 15, etc. I’m not sure what your point is. If you have a family of 7 or 11, you’re probably going to have a bad time using positional arithmetic regardless. The point here is that decimal is noticeably less efficient and less regular than some alternatives.

Maybe not. Case in point, our current time measurement system. We often talk about half an hour and a quarter of an hour. But almost never about a third of an hour or a fifth of an hour.

comex 9y ago
A third of an hour is 20 minutes, which we talk about all the time. We just don’t call it “third of an hour”…
- bhaak 9y ago
  Yes but that's not in relation to the hour but in relation to the sub unit of minutes. How often do you talk about 20 minutes because you can neatly stuff 3 of those time periods in one hour?
  - ajuc 9y ago
    25 and 50 minutes are more natural than 20 minutes from decimal POV. How often do you talk about them vs 20 and 30 minutes? I'd say the fact that 15, 20 and 30 fit nicely into an hour plays a role in their popularity, even if you don't realize you use them for that reason.
    - Dylan16807 9y ago
      > 25 and 50 minutes are more natural than 20 minutes from decimal POV. Not really. Quarter hours and half hours are natural units. This is true no matter how many minutes we divide an hour into. There's nothing special about "25" when you're building up from 1. 25 is only special when you're splitting up 100, and nothing uses 100-minute blocks so that doesn't happen. > I'd say the fact that 15, 20 and 30 fit nicely into an hour plays a role in their popularity I'm skeptical for 20. I think 20 being a nice round number plays a much bigger factor here. If hours were 65 minutes I think you'd see just as much use of "20 minutes".
      - ajuc 9y ago
        If 20 minutes was used because it's round, then we would expect 40 minutes to be used commonly. I'd say 45 minutes is used much more often. As for non-time-related units, I hear 25 deko more often than 20 deko when buying food. I don't think there's really a distinction between building up and down. When you're talking about 250 meters do you build up from meters or down from kilometers? I think both.
  - comex 9y ago
    > How often do you talk about 20 minutes because you can neatly stuff 3 of those time periods in one hour? Dunno. I personally 'visualize' 20 minutes as a third of an hour. I don't know how common it is to actually stuff an hour full of 20 minute periods, but it happens - you see a schedule with X:00, X:20, X:40. Multiples of 15 or 10 minutes do seem to be more common in that case. But it definitely matters to some extent that it's a divisor. Consider how rare 25 minutes is compared to 20 or 30. If you look at it only as a number of minutes, 25 seems a bit less 'round', but not too much; we often say "25 cents", after all. (And it's 5 squared and a quarter of 100.) But 25 minute periods are less convenient to calculate with, because adding them tends to result in odd/less consistent minute values, because it's not a divisor of 60.

mfukar 9y ago

I have a family of 6. I often divide a cake by 6. If my number system makes it more convenient to divide by 8, that doesn't really change my workload.

jacobolus 9y ago
Dividing by both 6 and 8 (also 2, 3, 4, 9, 12, 16, 18, ...) is easy in a duodecimal system. In a sexagesimal system it’s additionally easy to divide by 5, 10, 15, etc. I’m not sure what your point is. If you have a family of 7 or 11, you’re probably going to have a bad time using positional arithmetic regardless. The point here is that decimal is noticeably less efficient and less regular than some alternatives.