Hello!
I’m about to start the International Baccalaureate program in New Zealand and need to confirm my classes ASAP!
I would like to major in economics or business in university, however, I’m a bit concerned because I would like to do Math Studies instead of Math SL.
Would I still be able to attend a university in America, for example, NYU?
You can definitely apply. The danger you face is that Maths Studies is often regarded as a course where people have elected to decrease their course load (because unlike the SL/HL comparison, Studies counts as SL but is easier).
In general, for premier universities you want to demonstrate to the institutions that you’ve taken the most rigorous course possible, regardless of if maths is part of your desired degree. For Economics, you’ll need calculus at University (economics becomes calculus at a high level), so I’d recommend at least SL Maths. Many places ask for HL.
I’d advise at least trying SL maths. If it’s too hard, then you might need to take the risk, but I’m sure with hard work you’ll be fine in SL! 
Thank you so much for your reply! Definitely helped me!
NYU is my reach school, and I’ll definitely look into it more but I’d be just as happy at another school too.
I’ve decided that Math Studies is best for me, as I have struggled quite a lot with Math and feel that I should devote more of my time towards my HL’s rather than struggle with my SL.
I think it’s best if I stop worrying about what University I wish to attend and instead find a university that suits me.
Again, thank you for your help!
@jenniferjawright gained admission into NYU with Math Studies. She spent a lot of time on the SAT, extra curriculars, leadership and essays to help emphasise her strengths. People get into NYU with minimal or no mathematics, maths studies doesn’t cripple you but you will need to have strong competency in other areas
Also, this might help!
http://econ.as.nyu.edu/object/economics.1618.ug.req#major
Goes through the maths requirements for majoring in economics. They don’t offer transfer credit for HL Maths (for all requisite maths courses), implying that the maths knowledge must be more than commensurate with HL maths after the teaching of the degree is done.
Yes the general rule of thumb is that competitive US universities want to see your demonstrated critical thinking and collaborative learning abilities. A very one-sided course of study in high school that doesn’t necessarily provide much opportunity for you to demonstrate those skills may not be the best way to get them to notice you. However, like Jamie said, it isn’t necessarily an immediate barrier to entry. The other elements of your profile and personal narrative can fit the bill. Just be sure to keep in mind the importance of those elements, and think about how to show off your uniqueness as a thinker beyond your coursework.
The UK definitely do not allow you to study economics with Math Studies. The US is more flexible as you don’t need to declare your major until the end of your second year. So you can apply for “undeclared” as a major and then take some math courses in university to prepare for the economics/business major. Please do note that you will NEED to take advanced math ultimately for economics/business.