https://wbxpress.com/topic/urgent-need-vide-g-o-61-ses-dt-30-01-1996/ says that “…Any teacher appointed on or after the issue of this Govt. Order shall be allowed annual increments only when the training qualification of the teacher is relevant to his/her subject/group of appointment….”
This is not mandatory that you have to take your subject (here Math.) as 1st method in B.Ed.
If you are in Normal Section, you are appointed in Science Group (should be mentioned in your Approval). In that case, you may complete B.Ed. with any two subjects studied in graduation as your method subjects.
And if you are in H.S. Section, you are appointed in Math. (this should also be mentioned in your Approval). In that case, Math. must have to be one of your method subjects in B.Ed. But it is not necessary that Math should have to be the 1st method.
You will not, therefore, have to face any problem in future regarding incremental benefits.
