Effect of formal operation abilities on mathematics performance of Senior Secondary Students (SSS) in Kaduna State, Nigeria was investigated. The population of the study was all the SSS III students in the state. Their number was 62,565. A sample of 400 students of equal numbers of males and females was drawn, from those offering arts and science subjects. Two paper and pencil tests were developed and used to generate data for analysis, namely, Formal Operations Test (FOT) and Mathematics Performance Test (MPT).The FOT was to assess students’ level of formal operations while the MPT was developed to test their performance in mathematics. The results of the study showed that mathematics performance was low. Second, the numbers of students who always use and those who never use formal operations abilities were about equal. Third, results in the FOT and MPT were significant and positively correlated. Fourth, there was significant difference between the MPT scores of those students who always use and those who never use the abilities in favour of the former. Implications deduced were that this study confirmed that not all SS students use the abilities always and some never use them. Results of the analysis also indicated that formal operations significantly affect students’ performance in mathematics. Those who always use the abilities performed better than those who never use them. This indicated that the widely experienced poor performance in mathematics, especially among senior secondary students, is partly as a result of students not always using formal operations abilities. Lastly, findings indicated that knowledge of students’ level of formal operations can be used to understand, predict and improve their performance in mathematics. It was recommended that teachers of mathematics should endeavour to diagnose and identify their students’ level of formal operations so that they help raise those students who sometimes use and those who never use the abilities to be using them always. It was also recommended that governments should be convening and sponsoring workshops that will evolve programs for accelerating students’ cognitive development for use by teachers in normal mathematics lessons
Keywords: Kaduna, Mathematics Performance, Nigeria, Piagetian, Senior Secondary Students
