M.Sc

Yes, you can go for it. However, if you ignore your studies and practical, then the things will mess up. If you do not have high interest, understanding of mathematics and programming languages then you'll regret.

Yes, you can do M.Sc. At this stage, there is no problem with your leave of 3 years.

The candidate must have completed his/her graduation or equivalent from a recognized university.
Register and Apply:
Interested candidates can apply online with the required information.
Merit Screening:
Admission is based on the marks obtained in graduation.
For further information: https://www.shiksha.com/science/course/m-sc-in-mathematics-university-of-mumbai-kalina-santacruz-east-273585

IITs and NITs offer M.Sc in chemistry for the students who have completed their B.Pharma.

Fees of M.Sc in environmental science in Government Science College varies from 3000 to 18000 INR.

There are many universities in Canada for MS in finance. I think you should start application procedure for January intake as you will not get admission for September intake because their deadline starts from January so it would be difficult to get admission for September intake. Try for January, take a guide for proper application purpose and then pursue with your further process.

Please specify what you have done till now your qualifications and your bachelors details.