This document reports on research aimed at establishing effective methods for training Navy marginal personnel designated as Group 4. Preliminary investigation of training in mathematics showed that Group 4 personnel needed to improve in basic arithmetic skills and that they varied widely in their ability to acquire such skills. An experimental course covering basic arithmetic operations was developed to provide a standard set of training conditions which could be systematically modified. Results indicated that, in general, Group 4 personnel can benefit from instruction in all types of basic arithmetic operations. Also these students have the potential to use mathematics self-study materials effectively if class motivation is maintained at a high level. (RP)