Let’s start with the following question.
Urm, it’s a piece of cake.
Urm, if we expand the original expression a bit, a second approach is presented as follows.
The problem is here, if a F.2 student solves the question by following the second approach, he or she may not obtain the ‘correct’ answer. (Of course, a F.4 student knows the fact that can be further factorized as .) Similar ‘problem’ appears in questions like factorize . As a teacher, how to resolve the ‘puzzle’ in front of a F.2 student?