Math in one way or another permeates almost every field of endeavor. Even in everyday life it is almost impossible to go through a whole day without using math. If you cook, shop, commute, or even look at the clock, you are using math. We use math when we build, buy, travel, and grow. For the sake of brevity, let's just consider those fields that are mostly math based or that cannot be studied without a strong math background.
Teaching mathematics whether in grade school, high school, or the university would be the first field that comes to mind. After that, those who are involved in the nuts and bolts of the computer industry need strong math skills to develop hardware and software. This is especially true of those who develop programming languages and computer operating systems. Knowing binary and hexadecimal based math is requisite to any of these applications. Physics and chemistry both sit as strongly related to the math field. Without math, neither would have a basis to exist. Gas laws, acceleration, and velocity computations all require strong mathematical understanding.
While not considered math exactly, accounting deals with math from the basics to some of the more complex formulas when projections are needed. Economics is a math based field. The military uses math heavily in mapping, weapons guidance and targeting, and logistical areas. The largest single field when considered as a whole to use mathematics would be engineering. This can be stretched to encompass architecture and survey work.