Hi @jmtrik, Thank you for your interest in this question! I know that you have been working on this for the other types of MapleTA questions. In MathApp questions we seem to have a good opportunity to sort of 'communicate' via the startup code with the student and have his/her input automatically guided in the direction of the correct solution. The correction of syntax of an answer given into e.g. a TextArea box  is one first important issue. Another is the use of 'forbidden' operators in the answer box, i.e. like int(x^3, x)  when asked to hand in the value of the integral etc. A third issue is the possibility of communicating adaptive guidance towards the correct answer. All within the same single (possibly even randomized) question. I have uploaded two MathApps to the Maple Cloud as illustrations. You will see from the startup codes, that the syntax check there (by try/catch) is still somewhat ad hoc, and that in fact this particular check cannot catch the error stemming from the missing comma in e.g. [[8,9] [4,5]]. Moreover, some error messages are not particularly informative to the student. An example is obtained when you miss a parenthesis in e.g. [[8, 9], [4,5] .Other error messages are quite informative, for example the one you get when you write int(x, x = ...). I know that you can, of course, just count the parentheses etc. and communicate errors of such type easily to the student, but it would be very nice to have a general descriptive 'unfold' of all possible errors like for the int(x, x= ...). Do you know if such a list exists? And if it exists how can then the try/catch machine be used to show the 'unfolding' of a given error? I enclose here links to the two mentioned examples in the Maple Cloud (direct uploads of *.mw to the present platform seems to be impossible from this end): Input_Check_01 and  Input_Check_02 , Best, Steen