my first test mark

last class i got my first test paper and the marks i got really unbelievable. i got 24 marks over 25...!! it is really make me shocked. i didn't expect i can get that much coz i did not study very hard for the test. actually i just expect that i can only get 15-18 marks only. the single mark that i lost was cause by a silly mistake on the first question. the question is about algebra. i did not simplifly the last step. the question want x to as the subject but i gave x2 as the subject. if i be more careful, maybe i can get full mark for that test....