It is enVision right? The "explain your answer" is getting to us too! I finally stopped asking DD9 to try to write more or better explain her answer and let her just put down whatever she wants. Usually her answer is something along the lines of "because that is the answer". I jokingly told her to put because Mrs. Teacher (from kindergarten or 1st grade) told me that was the answer. I seriously want to let her use some of the in-depth answers others have given on this forum, but it wouldn't surprise me if she got in trouble for doing that and we don't need anything else causing her to get into trouble (she does fine on her own...lol).
I was recently complaining to a very wise person about the "explain why 9X1=9" question. I told her I didn't understand why this was even being asked at the 4th grade level, especially as "enrichment". She explained it to me like this - it might actually be a good question to ask a student that didn't know why, but when you have a child that has known 9X1=9 from a young age, then it becomes a foolish question to ask. I guess that makes sense.