Hello there. Hope you are doing good. I would like to tell you that in general, most of the countries offer M.Sc Computer Science instead of M.Tech or MCA degree as offered in India. The possibility of getting admission in a good college in M.Sc Computer Science abroad is difficult if you don't belong to Computer Science background since your application is assessed based on the stream of your bachelors degree and your work experience in similar field. Since your bachelors in Maths lacks computer science foundation subjects, the chances becomes quite less. However, if you can take a diploma or professional course in Computer Science, then there might be decent chances of getting admission in few colleges.

I hope you found this answer helpful. Good luck for your future.