Maths Eligibility

Yes, you are eligible for the post of Trained Graduate Teacher in Mathematics. Your B.Ed and B.Sc with Mathematics will qualify you for this post. For TGT posts, the candidate must have a Bachelor's degree in the concerned subject, in your case, Mathematics, with a B.Ed degree from a recognised college.
This will enable you to seek the TGT positions in a large number of states including Uttar Pradesh and many more whose qualifications match your background. Be sure at the time of application you fulfill the age requirements that exist for a state's education boards before you apply for TGT.

Yes, you are eligible to go for Biotechnology at IIT JAM. This is because maths is not a compulsary subject for Biotechnology. Thus, prepare well to get into IIT JAM. All the best.

For B.Com (Hons) and B.A Hons. Economics of DU needs Mathematics or Accountancy (For B.Com H) and Mathematics ( For B.A Hons Economics). Please seek admission in following UG programs of DU.

1. B.A. Hons Social work.
2. B.A. Hons. English (If English subject studied at 12th level).
3. B.Com.

The eligibility criteria of KVS TGT Maths is given below:

1. Bachelor degree in Electronics, EEE from recognised university with minimum 50% marks in the concerned subjects/ combination.
2. B.Ed or equivalent
3. Pass the CTET paper-2
4. Proficiency in teaching Hindi and English medium.

So, B.Ed, CTET are the additional requirements that needs to completed if not done earlier.

As per the eligibility criteria of M.A. Economics of DU's candidate should have any graduate/ PG degree in any subject from UOD or any Indian University recognised by the UOD with minimum 60% or fisrt division. Or B.A (Hons) in Economics from UOD with minimum 60% or first division. 

So Mathematics is not necessary here in graduation for admission in M.A Economics of DU's.

No you can't. You need to appear in JEE Main for getting admission in Maharashtra through All India candidature.

The eligibility criteria of LPU for MCA admission is given below.

Eligibility: Pass with 60% aggregate marks in BCA or B.Sc. (Computer Science) or B.Sc. (Information Technology) or any Graduation with Computer Science as a subject for three years or B.A. or B.Com. or B.Sc. (any Graduation) with (Mathematics or Statistics or QT or Business Math as one of the subject at Graduation or 10+2 level) or equivalent, subject to qualifying LPUNEST

So you can do MCA from here.

The eligibility criteria of TGT Maths for KVS is given below for an idea.

1. Bachelor's degree in Maths with any of the following subjects physics, chemistry, electronics, computer science, statistics.
2. B.Ed
3. CTET paper 2
4. Proficiency in Hindi and English

So from above BCA graduates are not eligible for TGT Maths for KVS.