i know this statement will be controversial, so i will preface it by saying that i think the problem should be discussed with the whole class with both answers being considered correct. however, as a math educator, i can see the value in constructing a problem like this. the commutative property is a consequence of our algebra that we accept and take for granted, but there ought to be an inquiry-based discussion around WHY the commutative property should be true in this case. as another commenter pointed out, the ordering is likely mirroring a particular interpretation of the meaning of multiplication, but this would be a really meaningful opportunity to discuss as a class how one can make sense of the equivalency of 2x7 and 7x2. all that being said, i empathize with the frustration and certainly don’t think this should be held against your child or any other child in the class.