# fractions with SI units package

Hey I'm trying to display the fraction of:

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:

What am I missing?

• What do mean with $16\,\dfrac23$? $16+\dfrac23$ or $16\cdot\dfrac23$? Nov 6, 2020 at 12:15
• 16+\frac23, I guess. 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... Nov 6, 2020 at 14:24
• Nov 6, 2020 at 23:11
• @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 :-;! Nov 7, 2020 at 9:53

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
\SI[quotient-mode=fraction,parse-numbers=false]{16\frac{2}{3}}{\metre\per\second}

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