Having produced the first batch of the K to 12 program graduates in the country in 2018, an evaluation of their acquired competence is one of the priorities of the government. This study analyzed the perceived, actual, and reasons behind the competence level in General Mathematics of 410 Grade 12 students. The study employed a General Mathematics Competency test to measure the students' actual competence, Rapid Competency Assessment Questionnaire to analyze students' self-perceived learned competence; and, interview schedule for the reasons for having the acquired competence. Results showed that the three areas of General Mathematics that include Functions and their Graphs, Business Mathematics, and Logic were perceived to be satisfactory by the Senior High School students, but the actual acquired competence was fair. On the specific learning competencies, data revealed that there are commonalities on the perceived most learned competence to their actual competencies. However, data indicated a very weak positive relationship between them. Statistically, there was no correlation between the two variables. Moreover, data revealed that factors affecting students' competence level revolved around the teacher, environment, low self-perception, and personal factors. The data indicated that senior high school students positively assess themselves in the learning of General Mathematics. However, the acquired competency showed that they have not yet mastered the necessary competencies in the subject matter.