Abstract: This True Experimental study compared academic performance of students in class VIII in initial tryout in one of the English Medium Schools of Vadodara, India among three methods of teaching arithmetic subject viz. (i) Conventional Method (in control group –C), (ii) Computer Assisted Instruction (CAI) only (in Experimental Group A - Exp A) and (iii) Computer Assisted Instruction with simultaneous discussion (in Experimental Group B - Exp B). After experimentation in the initial tryout, CAI was modified according to the comments given by the students of the groups (Exp A and Exp B), mathematics teacher and the observations made by the investigators.