Hey I'm trying to display the fraction of: enter image description here

But I'm not sure how to do it with the siunitx package.
This is what I got so far: \SI[quotient-mode=fraction]{16 2/3}{\metre\per\second}
But the result is not correct: enter image description here

What am I missing?

  • What do mean with $16\,\dfrac23$? $16+\dfrac23$ or $16\cdot\dfrac23$?
    – Bernard
    Nov 6, 2020 at 12:15
  • 1
    16+\frac23, I guess.
    – ivankokan
    Nov 6, 2020 at 12:20
  • I find that notation really confusing (saw first time when my daughter was at a school in Colorado, US). For me $16\frac{2}{3}$ has been $\frac{32}{3}$ since ever...
    – Rmano
    Nov 6, 2020 at 14:24
  • 1
    @Rmano en.wikipedia.org/wiki/Fraction#Mixed_numbers
    – ivankokan
    Nov 6, 2020 at 23:11
  • 1
    @ivankokan thanks for thr link! I assure you that, at least in Italy and Spain, that mixed fraction form is never used not taught... Multiplication is always assumed. That's worse than date format :-;!
    – Rmano
    Nov 7, 2020 at 9:53

1 Answer 1


The parser in siunitx does not attempt to 'read' fractions in the way you want: it ignores spaces so parses as 162/3. If you want manual formatting, you'll need to turn off the parser

  • You can't actually measure thirds or whatever, only 0.666... to some precision ...
    – Joseph Wright
    Nov 6, 2020 at 12:15
  • You can't actually measure 2 either. Only 2.000… (or 1.999…) to some precision. 🧐
    – Tom
    Apr 13, 2022 at 15:41

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