The demands in the education system, particularly the adoption of distance learning, vastly affected the teaching and learning and put a challenge in the conduct of assessment, including limitations in giving feedback. Hence, this quasi-experimental study developed Learning Activity Sheets (LAS) Using Interactive Formative Assessment and Feedback Mechanism and determined its effect on the Mathematics performance of Grade 9 learners at Bulan National High School, Bulan, Sorsogon. In the study, there was a total of ten (10) LAS developed. The learning activity sheets were designed to use interactive formative assessment which were formative assessments for both individual and group set-ups that resulted in four natures of interaction, namely: student-to-learning activity sheet, student-to-teacher, student-to-student (small group), and student-to-student (large group). These formative assessments were accompanied by and facilitated through feedback mechanisms that consisted of the source of feedback, online tools, feedback models, and manner of delivery which were: (1) Teacher's Feedback using Feedback Sandwich or Pendleton's Model of Feedback via Google Meet during the whole class discussion; and (2) Peers' Feedback using Situation, Behavior, Impact Feedback Tool via Google Meet and Messenger during whole class and small group discussions. After four weeks of utilization, it was identified that use of the developed LAS resulted in improved conceptual understanding, communication skills, and interest in learning math. Furthermore, the feedback mechanisms were found to have positive results for students along with understanding the lesson, completion of tasks, communication, interest in math, and social relationships. Thus, recommending its use and development for distance learning.