The 2-year Philippine Senior High School (SHS) commenced only in 2016. This phenomenographic study aimed to describe, explain and explore the teaching of SHS Mathematics to include problems encountered and interventions done by the teachers. Two schools in Quezon City were purposively chosen to be the study site with a maximal variation sampling where 8 teacher-respondents participated in the study. Classroom observation and one-on-one interview were conducted with the aid of self-designed protocols. The Teaching Guide for each subject was also analyzed. In analyzing the data, the 5 components of qualitative data analysis by O'Connor and Gibson were employed. After preparing and organizing the data, preliminary exploratory analysis and coding process were used to narrow the data into "text segments". Themes were formed through a 3-tier phase of layering to achieve saturation. Document analysis and external checking validated the findings. Results underscore that teaching SHS Mathematics is geared towards learner-centered, contextualized and relevant curriculum. Deficiencies along suggested teaching strategies, mathematical and technology tools, performance-based activities and training have prompted teachers to become flexible and resourceful in exhausting all means to effectively deliver the intended curriculum. Lessons which were inappropriate or repeated from basic education have been disregarded which decongested the contents and competencies. Low performance of students has been attributed to students' lack of mastery of basic skills, stigma, and language used which could be aggravated with books that are user-unfriendly and erroneous. Discussions, implications, and recommendations are given.