Is it possible to do a Master's in Mathematics after a Bachelor's in Economics?

I am currently an Economics student in my second year.I've come to realise that I'd like to study mathematics further (pure or applied) since I'm missing the subject ever since school ended. The maths in undergraduate Economics isn't too challenging.

There isn't too much flexibility in my university (I live in India and the education system is rigid) so I do not have an option to double major in Economics and Maths; although I will have two allied courses of Linear Algebra and Calculus as an add-on.

I've been a fairly good student in maths so far and I've already started to take on some of the undergraduate maths courses on my own. Would a good maths GRE score be sufficient to apply to a good university in the US? Could I also apply for an M.S. in Statistics?