You can fill this below MATHS OPTIONAL ADMISSION FORM and then make the payment for choosen course.
If you are preparing any of these examinations of IAS/UPSC/CSE-Civil Services Exams and IFoS/IFS,
State PCs examinations like BPSC, UPPSC, WBCS, HPSC/HCS, JKCS/JAS, OPSC/OAS.
