There are few codes you might come across.
CNE = Correct Numerical Expression
This means that you'll get the full mark for an expression which works out to give the correct answer. For example, if the correct answer to a trig question is 19.41 m, and you write 24 sin 54, you may get the mark. Of course, it's best to finish the question off properly.
CFPA = Correct From Previous Answer
If you've made an error in, say, part (i) of a question and then taken your answer from that part and used it correctly in part (ii), you'll get the full marks, even though your answer is not the same as the correct answer to that question. In other words, if you only make one mistake, you'll only be penalised once.
ISE = Ignore Subsequent Error
You might work all the way through a question, get the right answer, and then foolishly go on and do something foolish. You'll get the mark because you've got there even though you then made a mistake after it.
TE = Transcription Error
Sometimes it's easy to see that a student copies a number from the question paper down incorrectly, such as writing 5355 instead of 5535. A marker may ignore this error and mark it as if it was correct.
Hope this helps.