This paper investigates the activation of students' prior knowledge for the development of vocabulary, concepts and mathematics. It has been observed that many secondary school students are not performing well in the examination conducted by the West African Examinations Council and National Examinations Council of Nigeria. The situation became worrisome because of the dwindling performance of students in English Language and Mathematics which are compulsory subjects for securing admission into tertiary institutions in Nigeria. Four research questions were formulated and translated to test whether a significant difference exist between students' achievement in comprehension in English Language and Mathematics before and after the treatment. The study is a quasi experimental which involves two hundred and sixty students selected through random sampling technique. The experimental sessions lasted six weeks. The experimental groups were engaged in collaborative work in smaller groups where they discussed issues related to the new topics using their prior knowledge. Experimental and control groups were given pre-test before the commencement of the study and achievement test after the experiment. The data collected was subjected to t-test statistics and the findings of the study show that the students in the experimental group performed better than those in the control group.