I bought a Casio Prizm CG20 earlier this year and on the box it says that it is allowed in A level exams, but doesn't specify which exam boards. I'm fairly sure that it can't do symbolic differentiation or integration, but i would like to just confirm that on here? Also if it does have retrievable storage then how do i enter the test mode or would the fact that it has such a feature entirely prevent it from being allowed in an exam? In June i am doing Maths, Further Maths, Physics and Chemistry AS exams and while i do not need the calculator to succeed, i would like to bring it in to use anyway. Finally, if it is allowed in the exam what should i do to make an invigilator aware that it has been put into a test mode or should i just let them reset it entirely with the reset button on the back?