A. "=" means that you should write on the right the answer to
the calculation on the left.
This is the same as the (mis)understanding that "=" means the answer
comes next.
Yes. This is overwhelmingly the way in which most children
think about the = sign by the end of elementary school. It
reflects an undesirable homogineity in the way we write number
sentences in elementary grades. Unfortunately, this way of
thinking makes algebraic topics more difficult for many children.