اعراب اخوك محب درس الرياضيات

Your brother, who loves studying mathematics, is in the case of being a beginner because he is a proper noun and the pronoun “كاف” is built on the “فتحة” in the position of the word that has been added to it. The word “محب” is in the case of being a predicate with a “ضمة”. “Studied” is in the case of being the object with a “فتحة”. Mathematics is in the case of being added to with an “كسرة”.