Calvin hates school, simply because he finds no meaning in the things he learn there. It also seems like school is a bit to serious for him. Here he is not given the opportunity to develop according to his own wishes and imagination.
The result of this "forced learning" is that Calvin doesn't take school very seriously. As far as his homework is concerned, it is only done when his parents make him do it. (Or whenever he gets Hobbes to do it for him...)
Calvin would rather play and figure out life on his own. His philosophy is: "Childhood is short, adulthood lasts the rest of your life". Because of this conclusion it is vital to take as much advantage of childhood as possible, instead of wasting valuable time at school! Sadly enough, his parents doesn't share this view, they would gladly see their son spending a bit more time on school. After all, he needs an education to get a job when he's older! Calvin however doesn't consider this a problem at all, he is going to inherit his father!
The six year old's minimal interest in school has often led to intervention from his parents among others. When junior occasionally decides to skip school, his mother is forced to chase him through gardens and over fences to get him back to his desk...
The principal is a person that Calvin has gotten to know very well, in a very short time. At least one visit a day to his office is normal, and the file he has on the little boy has developed into a huge archive!
The teacher, Mrs.. Wormwood, is a person Calvin strongly dislikes. Simultaneously he has a certain respect for her, and occasionally he even seems a little afraid of her. This is not so strange really, thinking about how often she sends him to the principals office. Even if Calvin often deserves this treatment, it must be said in his defense, that Mrs.. Wormwood is not very understanding and shows extremely little patience with him.
When you hate school and skip your homework, how on earth will you ever pass any tests? Calvin's solution is simple - cheat! The best way to cheat is to use the best source for information, and Susie is undoubtedly the best. The only problem is that she often strongly resists to help him cheat. But, what can she do when Calvin sits right behind her and explores her answers with a telescope...?
When Susie won't help him, he has to figure out other solutions. Like this one:
IT'S WORTH A SHOT.
The one thing that Calvin does like at school is "show and tell". Here the children may bring personal items (like pets, toys and so on) and tell the class about this. This is the only time at school when Calvin feels he can assert himself, by using a talent he really possesses, imagination! To his teacher's despair he holds forth with great enthusiasm about his meetings with aliens and dinosaurs from the late cretaceous period and more...
It probably speaks for itself that Calvin's grades are not among the things he talks most about. E's and F's are, to our knowledge, the only grades he has achieved. However, this kid's grades is not representative for his IQ, a fact that probably brings his parents much relief... Calvin is without doubt extremely smart! His knowledge and use of foreign words and technical terms is, to put it mildly, astounding for a six year old!! So, Calvin is far from stupid, he only sucks in totally useless knowledge. It doesn't help much to know all the members of Captain Napalm's brigade when you can't figure out 12+7...