Order of operations - what is 6÷2(1+2) ?

[rprosperi]

(12-12-2020 09:46 AM)Hlib Wrote:  The calculator manual always specifies the priority of operations, so we can use private rules to get rid of ambiguous interpretation.
Implied multiplication and division has a higher priority than normal multiplication and division. Operations with the same priority are performed sequentially from left to right. And that`s where all the arguments end.
6◢2(1+2)=(6÷2)×(1+2)=9 (CASIO)
6÷2(1+2)=6÷(2×(1+2))=1 (CASIO, TI-85,86)
6÷2×(1+2)=(6÷2)×(1+2)=9 (CASIO, TI-83,85,86,89, HP-50G)

I've seen people claim this priority, but have never seen this is in any mathematics book, nor ever found a mathematician or teacher that agrees. Do you recall where you learned this or have any reference?