In this paper, we present the concept of problem-based learning as a tool for learning Mathematics and Chemistry, and in fact, all sciences, using life situations or simulated scenario. The methodology involves some level of brain storming. Here, active learning takes place and knowledge gained by students either way through a collaborative learning situation becomes personalized within the group. This underscores the need for the integration of the curricular of some basic concepts in Mathematics and the sciences in general from the school level; thus it makes it easier for students in the tertiary educational level to learn higher and applicable concepts. Three cases were discussed involving PBL namely: Graphical interpretation of experimental readings in a Chemistry/science laboratory as it enhances or makes use of basic mathematical knowledge, calculus in Chemistry and lastly, the integration of curricular for Mathematics and the basic sciences at higher secondary and lower university levels. Problem-based learning method then becomes an enviable tool which can be used in teaching both Mathematics and Chemistry at the secondary and tertiary levels.