The kid's answer is the only correct answer. It's not half right, or 5/6 or 4/6 right. It's the only correct answer that fits the question. The teacher is a moron who has no business in a math classroom except as a remedial student.
Reaper is nifty, but it's not FOSS, which would be the only reason why I'd give up Bitwig. (I know that's not what the thread asked, but that's my reason for not using Reaper.)
I have a bad feeling about this.