This book focused on determining the effect of the use of Gen-Math Machines which are manipulatives or teaching tools in one of the core subjects of Senior High School, General Mathematics. The teacher-researcher asked the learners to develop Gen-Math Machines that would elicit the things that they are learning in General Mathematics, and those machines were used in enhancing skills of learners in General Mathematics. One hundred forty-four became the respondents for this study, and they were the grade 11 learners of Talangan Integrated National High School, Nagcarlan, Laguna, Philippines, school year 2017-2018. The Gen-Math Machines improved learners' concept and skill in mathematics. Recommendations to mathematics teachers, department head, school heads, family, community and future researchers were laid down at the end of the study.