The purpose of this study was to ascertain the effect of Multimedia Projection on Senior Secondary Students? achievement and interest in Sets. Four research questions and six null hypotheses guided the Study. The design of the study was quasi-experimental, non-equivalent Control Group Design. This design was apt since randomization of subjects was not done and intact classes were used. The population for the study was 2,809 SSI students made up of 1,246 males and 1,563 females and the sample size was 200 students from the four intact classes used for the study. Each intact class came from one co-educational school used for the study-two from Nsukka zone for experimental and control groups. Similarly, the other two came from Enugu Education zone, one for Experimental and the other for Control group. Multistage sampling technique was employed for the study; purposive sampling was used in selecting four state schools with functional computers. The four intact classes used were therefore purposely drawn from the four coeducational schools in Enugu State of Nigeria. Balloting without replacement was used in determining which of the two schools, in each education zone, becomes the Experimental group?s school and which one becomes the Control group. The instruments of Set Achievement Test (SAT) and Set Interest Scale (SIS) were used to collect data on the cognitive achievement and interest of students in Sets respectively. The four research questions were answered using means and standard deviations while Analysis of covariance (ANCOVA) was used in testing the hypotheses at 0.05 levels of significance. The results revealed that the use of MUMPPAS in form of CAL package as a teaching method increased students? achievement and interest in sets more than the conventional chalkboard method of teaching. Both male and female students achieved highly as a result of the use of MUMPPAS and there was no significant interaction effect between MUMPPAS treatment and gender on students? achievement in Sets also interest of male and female students.