Note: Closure does not automatically imply that the question is non-mathematical. I agree that there are interpretations of the question which make it on-topic and useful to folks, but that does not necessarily mean that we must keep it open.
The close reason is not quite right unfortunately, but I do agree with the closure, and that is not because it is basic (i.e. you seem to be deriving the wrong conclusion about the reason for closure), but because it is a dupe of one of the following, based on how you interpret it (thanks to Didier for the list).
What is the standard interpretation of order of operations for the basic arithmetic operations?
Do values attached to integers have implicit parentheses?
What is 48÷2(9+3)?
Also, the main question seems to be (ignoring the motivation): "Why my calculator does not follow a (supposed) rule". In one interpretation, that question (about the calculator) is not really mathematical, and is more about the interface on how to input numbers and figuring out the precedence which the calculator uses, and is out of the scope of this site. This was the reason I cast the last close vote (hastily, I admit. To be fair to myself :-P, I knew that in another interpretation, the question is a dupe).
Basic questions are welcome on this site.
Badly written, ambiguous dupes of existing questions, at whatever level, are not.
Also, closing a question does not mean it is gone forever. The OP can edit the question to make it clearer, and then the question can always be reopened (perhaps by making a meta post, like you did).