I can't speak for others, but here are the reasons I strongly dislike them:
They're low-effort. You can ask the same question for any numbers, any sources, and any set of allowed operators. What makes any individual puzzle of this type special?
They're often ill-defined. Many of these questions allow "any standard operator" without specifying what ...
First of all, if all you want is our actual policy then
you can find it in this question:
Proposed policy on mathematical questions
The policy described there is, briefly:
A question is off-topic on Puzzling if it is routine.
This means that the question can be answered by following a standard procedure.
Other related considerations: is the ...
No, this shouldn't be a close reason.
Each individual SE site's scope and policies should exist in a vacuum, separate from other sites. Of course there are some network-wide policies which we have to follow since we're using SE's platform (although even some of those aren't applied for Puzzling specifically), but otherwise we should be able to decide our own ...