Some parents are more immature than their kids. Ask them with no emotions if this cat is still alive, if yes, do sth to have better grades at school and than try talking to them that u understand that school is first, u understand your mistake, and so on and now you feel ready to handle school and cat both in your life and ask them for this chance and giving cat back. U are 100% correct in this situation, but only because they parents u need to lower your standards to meet their insane and maby magical ways of thinking. They stand that your cat is in power to affect your math skills and breaking this relation will make your brain more focused on mathematical cases.....rather no proves it works like this