A study compared the benefits of using the Hewlett-Packard HP-41CV hand-held computer, as opposed to conventional training without computers, in teaching mathematics to fire control systems repairers. Thirty soldiers in a course to train fire control systems repairers received training in technical mathematics using the hand-held computer, whereas another 30 soldiers enrolled in the same course were presented the same course material, but without the use of computers. An end-of-training mastery test, which was administered to both groups, failed to reveal any statistically significant differences between the two instructional approaches. Flaws in the design of the evaluation study prevented the researchers from determining whether there really were no differences in the relative effectiveness of the computer-aided and conventional methods of instruction in the particular course under investigation or whether the lack of any statistically significant differences could be attributed to such factors as differences between entry-level mastery of course material, different amounts of training received by the two groups, or the administration of an end-of-course test that was not difficult enough to reveal proficiency differences between the two groups. It was recommended that these factors be taken into account when similar studies are planned in the future. (This report includes the instructor manual for the computer lesson.) (MN)