math.stackexchange.com has handsome CSS styling, but 0 (zero) and o (lowercase O) are visually nearly indistinguishable. That's ironic for a math forum (n0)?

I'd suggest using a font that features a distinctive zero.

(meta meta question: Am I the only one that's bugged by this? I didn't see other meta questions on this.) Update: anorton correctly points out that there has been discussion on using "non-lining" digits in Why does the font use text figures (“lowercase digits”)?.

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    $\begingroup$ I think rendering 0 in $\LaTeX$ is a good idea here. It renders as $0$ which is distinctly different from o, O, $o$ and $O$. Whenever writing any numbers in a math paper or here on MSE, I always put it in $\LaTeX$. $\endgroup$ Commented Jan 28, 2015 at 0:23
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    $\begingroup$ Related: meta.math.stackexchange.com/q/10317/23353 $\endgroup$
    – apnorton
    Commented Jan 28, 2015 at 0:47
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    $\begingroup$ @CameronWilliams For a math paper, the difference is extremely minute with default fonts (Latin Modern). Comparison: I'm not even sure I can see it or if I'm imagining it. But here on MSE that's much more important: 0$0$. $\endgroup$ Commented Jan 28, 2015 at 10:20
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    $\begingroup$ @CameronWilliams this might be a personal stylistic choice yet is not recommended practice in general. $\endgroup$
    – quid
    Commented Jan 28, 2015 at 12:13
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    $\begingroup$ Oh wait. You're right. I used to put numbers in LaTeX in papers until I noticed exactly what you just did. However I do put numbers in LaTeX here. $\endgroup$ Commented Jan 28, 2015 at 12:51
  • $\begingroup$ Do you have a genuine example where this could cause any confusion, actually? $\endgroup$ Commented Jan 28, 2015 at 18:11
  • $\begingroup$ I thought that $0$ and o are quite distinct up until now. Or do you want to insist not to use MathJax for writing mathematics in a clear way, and just complain about it? $\endgroup$
    – Asaf Karagila Mod
    Commented Jan 28, 2015 at 18:24
  • $\begingroup$ apparently CSS is en.wikipedia.org/wiki/Cascading_Style_Sheets $\endgroup$
    – Will Jagy
    Commented Jan 28, 2015 at 21:54
  • $\begingroup$ @NajibIdrissi: One example: "x ranges from t0 to t1". Another (which prompted me to create this post): math.stackexchange.com/questions/1122094/…. As an aside, I'm proud that every meta stack exchange post I've made has ended up getting me negative points. :) $\endgroup$ Commented Jan 29, 2015 at 5:50
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    $\begingroup$ @fearless_fool: The first should be written as "$x$ ranges from $t_0$ to $t_1$." Similarly, you can use dollar signs in the post you linked to to improve readability, including but not only for the numbers. $\endgroup$ Commented Jan 29, 2015 at 6:52
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    $\begingroup$ @fearless_fool I said a genuine example. If you're too lazy to use mathjax when it's clearly warranted, that's your fault, not SE's fault. And even without mathjax your post wasn't confusing... And I don't really understand what kind of pride you can take in people disagreeing with you. $\endgroup$ Commented Jan 29, 2015 at 7:48
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    $\begingroup$ @CameronWilliams you could write a whole question self answer thread on academia stack exchange just based off this comment. It might even be useful for people new to the field. $\endgroup$
    – user400188
    Commented Sep 12, 2020 at 4:36

1 Answer 1


When writing I try to follow 3 rules. If followed, your 0 vs o is not an issue.

  1. Use math mode for maths. For example, if I have $10$ orangutangs and I buy $32$ more then I have $42$ orangutangs.
  2. Spell out the numbers for small numbers. For example, "follow three rules" but not "follow thirty-three rules". (The first journal I submitted to stipulated that I do this, and I have done so ever since.)
  3. Use the normal numbers the rest of the time. For example, I bought lots of orangutangs in January 2015.

A related TeX.SE answer is here. Notably, this answer includes the a quote from Donald Knuth (the man behind $\TeX$).

The following is an excerpt from Knuth's article "Typesetting Concrete Mathematics" (TUGBoat, 1989) [Aside: The textbook Concrete Mathematics was typeset using Concrete Roman as the text font and Euler as the math font]:

There was, however, one significant difference between typing the manuscripts for Concrete Mathematics and for The Art of Computer Programming, caused by the fact that the Euler numerals $0123456789$ are distinctly different from the numerals 0123456789 in ordinary text. [...] This experience ... taught me that there is a useful and meaningful distinction between text numerals and mathematical numerals. Text numerals are used in contexts like '1776' and 'Chapter 5' and '41 ways', where the numbers are essentially part of the English language; mathematical numerals, by contrast, are used in contexts like 'the greatest common divisor of $12$ and $18$ is $6$', where the numbers are part of the mathematics. [...] Equation numbers presented us with one of the most perplexing design questions. Should those numbers be typeset in Euler or cast in Concrete? After several experiments we hit on a solution that must be right, because it seems so obvious in retrospect: We decided to set equation numbers in an "oldstyle" variant of Concrete Roman ...

Interestingly, I notice when typing this answer that the typefaces are different for typing and for reading - the typing typeface has a slashed zero, which is designed to get rid of the ambiguity you mention.

  • $\begingroup$ "the typing typeface has a slashed zero" -- exactly my point. if I was writing a technical paper, then sure, I'd use TeX. But MS should be a place where it's easy to pose a question. Why should the choice of font force you to drop into TeX every time you want to write a number? $\endgroup$ Commented Jan 28, 2015 at 15:29
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    $\begingroup$ The typeface for composing a question/answer/comment has a slashed zero because when you're composing something, there is no formatting, so if you are typing code, math... then the font should be unambiguous, because the formatting won't be able to help you. But once you've submitted it, your submission is properly formatted so that's not important anymore. The typeface for composing is also fixed-width, for example, but only code blocks are fixed-width once submitted. And anyway I have yet to see a single instance of 0/o ambiguity causing a problem on MSE. $\endgroup$ Commented Jan 28, 2015 at 18:08
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    $\begingroup$ @fearless_fool "Why should the choice of font force you to drop into TeX every time you want to write a number?" A similar question, but in terms of StackOverflow, would be "why make me super-indent my code to make it have a grey background and syntax highlighting? StackOverflow should be a place where it's easy to ask a question, and I shouldn't have to implement code-format syntax to post my question." A necessary step in attaining the goal of being "expert community" is having high-quality questions. High quality questions need proper formatting. $\endgroup$
    – apnorton
    Commented Jan 28, 2015 at 18:45
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    $\begingroup$ @fearless_fool to put those numbers that are part of the mathematical content in math-mode conveys semantic information. You should thus do this regardless of the look of the figures. $\endgroup$
    – quid
    Commented Jan 28, 2015 at 20:56

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