Searching this thread for the string "just because it only uses some basic math, it cannot be sentient/conscious/intelligent" I can only find it in your comment. That's your interpretation of what the OP said, not what they said, is that correct?
I think you should not try to interpret in that way and only stick to what the other person has said, otherwise we will all lose the thread of the conversation.
In any case, nobody here has said anything about brains having, or not having, to do something with matrix multiplication, except for your comment, so I still don't understand what you are saying.
Are you saying that the OP's brain is doing "something that couldn't be done with "matrix multiplications", or are you saying it isn't doing something like that?