Do not treat everything between two $ as TeX math

[kfiven]

Typing $1 instead of $2 should not be treated as TeX math

The opening $ must have a non-space character immediately to its right, while the closing $ must have a non-space character immediately to its left, and must not be followed immediately by a digit. Thus, $20,000 and $30,000 won’t parse as math.

[ginnyTheCat]

Wouldn't these rules block something like $1 + 1$ as well?

[kfiven]

The rule is for the cases where we should parse input as TeX.

[kfiven]

so as per the rule $1 + 1$ will be a valid TeX.

[ginnyTheCat]

Ah sorry, I misread that the opening one is not allow to be followed by a digit instead of the closing one.