(1) I don't think I did very well in this exam. Except for these questions, all the others should be answered correctly, but I didn't check some questions carefully, I just glanced at them.

(2) careless calculation, careless calculation.

(3) Numbers are always copied wrong.

(4) I didn't check it carefully after I finished it, which led to some simple questions being wrong because I didn't check it.

(5) the definition is not proficient.

Some people can change their mistakes.