This document is a mathematics assignment written by Muhammad Pachroni Suryana (0031419) for the Electronics A class at the State Polytechnic of Bangka Belitung. It contains practice problems on integral substitution and combinations for Semester 3 of the 2015/2016 academic year. The assignment was written for the Manufacturing Engineering course at the POLITEKNIK MANUFAKTUR NEGERI BANGKA BELITUNG located in the Air Kantung Industrial Zone.