Because it’s just a mnemonic to remember what the order of operations is, not like… What the order of operations is, which you should know already if you know the mnemonic.
Because it’s the only other thing about that system at all. OP wasn’t teaching, just showing what that system does. If you looked for a source that explains it you’d be told
And how is Aunt Sally going to learn if you don’t say that from the start?
Because it’s just a mnemonic to remember what the order of operations is, not like… What the order of operations is, which you should know already if you know the mnemonic.
Because it’s the only other thing about that system at all. OP wasn’t teaching, just showing what that system does. If you looked for a source that explains it you’d be told