The study investigated the effects of using Learning Trajectories (LT) in Mathematics and Chemistry on secondary students’ understanding of word problems in Rivers State, Nigeria. The study used a quasi-experimental pre-test /post- test control design. A sample of 84 (54 male :30 female) senior secondary two (SS2) students was purposively selected from Federal College of Education (Technical) Demonstration secondary school Omoku in Ogba/Egbema/Ndoni local government area. Four research questions were answered and four research hypotheses were tested at 0.05 level of significance. Data was obtained through a Test of Basic Skills on Word Problems (TBSWP) designed by the researchers. The reliability coefficient index r=0.82.Mean scores were used in analyzing the research questions while z-test was employed in testing the hypotheses. The findings revealed that learning trajectories (LT) [rigid operational, flexible operational, basic operational levels etc] enhanced students’ academic achievements in mathematics. Based on the findings, it was recommended that the use of learning trajectories to teach mathematics should be encouraged in senior secondary schools.
Keywords: Learning Trajectories, Mathematics, Word problems., students’ understanding