On 2013–07–31 Sietse Brouwer wrote:

> Tangential to your issue, but nota bene: instead of $...$ for inline
> math, ConTeXt lets you use \math{...} or \m{...}.

Indeed. And when you use \asciimode, you have no other choice (and
that's a good thing):

  \asciimode
  \starttext
    My #1 is $5

    \math{a^2 + b^2}
  \stoptext

Marco