mixed fractions have too much space

Question

Mixed fractions have too much space, which they don't in other $\TeX$ systems; for instance, 1\frac12 produces $1\frac12$, with the fraction too far away from the integer part.

Answer 1

Don't use Arturo's workaround. As Bill Dubuque said, version changes in MathJax can easily make your $\frac12$ end up sitting on top of the $1$. Instead, put the \frac in braces or \mathord

This is what $1\frac12$ looks like: $1\frac12$.

This is what $1{\frac12}$ looks like: $1{\frac12}$.

And this is what $1\mathord{\frac12}$ looks like: $1\mathord{\frac12}$.

By placing the expression inside braces or using \mathord, you are preventing the extra space (due to the way MathJax is being slightly less sophisticated about handling fractions: outside of mixed fractions the spacing is generally preferred) from being inserted. This way even if MathJax were to be updated to reflect the usual logic that "fractions after a numeral is to be interpreted as mixed fractions without the customary extra space" your expression won't break.

For example:

This is $1\!{\frac12}$: $1\!{\frac12}$

And this is with two negative spaces: $1\!\!{\frac12}$.