It very much depends on the application. Econometrics uses lots of statistics. Finance uses stochastic calculus. Microeconomics uses linear algebra and calculus

It very much depends on the application. Econometrics uses lots of statistics. Finance uses stochastic calculus. Microeconomics uses linear algebra and calculus. To see how incomprehensible things can get, here's a paper by one of my old econometrics professors: http://econweb.ucsd.edu/~bbeare/pdfs/vinecopula.pdf http://econweb.ucsd.edu/~bbeare/pdfs/vinecopula.pdf