Well now, you see, you erred as well. He didn't mispell grammar, as grammar is an entity or area of knowledge not susceptible of spelling. He mispelled 'grammar', the word which represents grammar in english.
Hey, let me give the test. Nobody would pass! Someone else wondered what the test was actually like, and I share that curiosity. I suppose if I took it I might end up with a failing grade and a beef on every question.
Perhaps, but you misspelled 'misspell.'