In around 1980 I heard that the U.S. Army Corps of Engineers and the Field Artillery were vitually tied for which branch had the highest wash-out rate in their Officer Basic Courses. At the time CE narrowly won because FA recycles more of its OBC failures into the next OBC class. CE and FA OBCs are more math- and computationally-intensive than the other OBC schools.

Enlisted FA and and Infantry mortar guys having fire direction MOSs have high math scores on their AFQT exams (military entrance exams), college degree or no degree. In spite of that many in command at company, battery and battalion levels worry about what their flakier FDC guys might do during live fire situations ...