This teaching practice project (TPP) based on the add-subtract-multiply-divide four-learning-stage in the elementary school to let students to realize what is the stage of Engineering Mathematics (EM). Integrate the class, homework, and exams as the same teaching materials which are fully covered sub-problems with simply coefficients to reduce the difficulty of learning EM. Flipping class with YouTube films can assist student to preview the materials. Cloud calculation bade on Matlab is the learning-by-doing approach to promote the active participation of students in EM. In order to achieve the "Most don't give up" class management, the immediate feedback of IRS, Line, as well as oral verifications of class materials by students can use to adjust the subjects of remedial teaching. There are three results after implementing the TPP. (1) It is a good result that around 80% of students can understand and oral illustration of the solving procedure of class materials. (2) It is a fair result that around 60% of students can pass the open-book test based on the same teaching materials with new coefficients. (3) It is a non-good result that only 50% of students can pass the close-book test with the same teaching materials. There are three reasons can be found after analysis. (1) The error of calculation of students always play an important role to reduce the completion of solving problems even though they know the solving procedure. (2) Many approaches to solve the same problem should result in the same answer, but most students cannot debug in time due to non-proficiency. (3) Due to declining birthrate, the gap between students in our department has increased, so the original remedial teaching should also be adjusted to reduce the gap for improving their learning efficiency. A new TPP has been proposed this coming academic year to achieve the mastery learning during the non-class period. (1) Flipping class with verification of student preparing lesson: After previewing each sub-problem film, then students can record their own illustration of solving procedure and upload it to YouTube for verification of their preparation lesson and understanding of the sub-problem. (2) Dynamic remedial teaching: Encourage students to attend sub-problem written test after understanding the sub-problem. (3) Make-up test with reviewing and debugging ability: Students can photo their answer sheet of the sub-problem written test, and request the make-up test after reviewing and debugging of photos of answer sheet.