Military and civil mathematics mainly tests advanced mathematics, such as function, sequence, matrix, probability theory and so on, which is relatively difficult. If you are interested in mathematics, or have a good foundation in mathematics, then choosing this direction may be more advantageous.
Civilian management in military and civilian areas mainly focuses on organizational behavior, leadership, human resource management, strategic management, marketing and other aspects of knowledge. If you have a strong interest in management theory and practice, or have good organizational and management skills, then choosing this direction may be more advantageous. In addition, the military and civilian administration also has certain advantages over competition.
To sum up, you should choose the best one according to your own situation and personal preference.