5 ms·

Yes, but you'll see "decimal" more in the wild, and that's what people mean by it. "You write it with a decimal point", and they do usually mean to include the

Yes, but you'll see "decimal" more in the wild, and that's what people mean by it. "You write it with a decimal point", and they do usually mean to include the irrationals. So, yes, real numbers, but the reasoning behind their usage is "you write it with a decimal point". I'd bet more people understand "decimal number" used in that sense, than understand "real number".

bombolo 3y ago
i've never seen an irrational number written in digits in my whole life. Have you????? I've seen them expressed as letters or formule
- yamtaddle 3y ago
  Never. Never in school? It's totally normal in the US, it's the reason as many people know that π starts "3.14" as do.
  - bombolo 3y ago
    Yes never, not in school, not in analysis, and certainly not in numerical analysis. You've proved my point. It's either π or 3.14. Except that the latter is a rational number :)
    - yamtaddle 3y ago
      > Yes never, not in school, not in analysis, and certainly not in numerical analysis. Weird, I just assumed that was normal in most education systems. I don't know how you'd get a sense of the rough scale of various common irrationals, without having some idea what they look like when represented in decimal notation. Such representations are normal starting not later than when we start seriously working with circles, in US school, and never really stop coming after that. Estimation exercises lean heavily on having some idea of the decimal representation. > You've proved my point. It's either π or 3.14. Except that the latter is a rational number :) Never claimed π is 3.14, so no, I didn't at all prove your point. I wrote that it's very well known that it starts that way. When a normal person says "decimal number" they mean to include π, because any usefully-precise decimal representation of it's going to involve a decimal point. At least in the US, they saw it represented "3.14..." or "3.1459..." or whatever, many, many times in school. It's obviously, to a non-mathematician, a "decimal number". They mean "the real numbers" (or, perhaps, depending on context, exclusively the parts of the reals that aren't whole integers), except that name is harder to remember than the incorrect (but more common and intuitive) "decimal numbers".
      - bombolo 3y ago
        Can you write here an irrational number, not in the form of a letter or a formula? For me a "decimal number" is a number represented in base 10. Which is why I was asking. I even googled and there is no real definition.
- paulddraper 3y ago
  3.14...
  - bombolo 3y ago
    Isn't that equal to 157/50?
- someweirdperson 3y ago
  > i've never seen an irrational number written in digits in my whole life. Have you????? I'm currently reading one. Looking good so far. I'll let you know after I finish.

bombolo 3y ago

i've never seen an irrational number written in digits in my whole life. Have you????? I've seen them expressed as letters or formule

yamtaddle 3y ago
Never. Never in school? It's totally normal in the US, it's the reason as many people know that π starts "3.14" as do.
- bombolo 3y ago
  Yes never, not in school, not in analysis, and certainly not in numerical analysis. You've proved my point. It's either π or 3.14. Except that the latter is a rational number :)
  - yamtaddle 3y ago
    > Yes never, not in school, not in analysis, and certainly not in numerical analysis. Weird, I just assumed that was normal in most education systems. I don't know how you'd get a sense of the rough scale of various common irrationals, without having some idea what they look like when represented in decimal notation. Such representations are normal starting not later than when we start seriously working with circles, in US school, and never really stop coming after that. Estimation exercises lean heavily on having some idea of the decimal representation. > You've proved my point. It's either π or 3.14. Except that the latter is a rational number :) Never claimed π is 3.14, so no, I didn't at all prove your point. I wrote that it's very well known that it starts that way. When a normal person says "decimal number" they mean to include π, because any usefully-precise decimal representation of it's going to involve a decimal point. At least in the US, they saw it represented "3.14..." or "3.1459..." or whatever, many, many times in school. It's obviously, to a non-mathematician, a "decimal number". They mean "the real numbers" (or, perhaps, depending on context, exclusively the parts of the reals that aren't whole integers), except that name is harder to remember than the incorrect (but more common and intuitive) "decimal numbers".
    - bombolo 3y ago
      Can you write here an irrational number, not in the form of a letter or a formula? For me a "decimal number" is a number represented in base 10. Which is why I was asking. I even googled and there is no real definition.
paulddraper 3y ago
3.14...
- bombolo 3y ago
  Isn't that equal to 157/50?
someweirdperson 3y ago
> i've never seen an irrational number written in digits in my whole life. Have you????? I'm currently reading one. Looking good so far. I'll let you know after I finish.