The current era presents a daunting challenge for highly ambitious young individuals due to the highly competitive environment that prevails worldwide. Employers prefer only the toppers, which is why competitive examinations are organized for final selection. Candidates ability is judged based on general mathematics and aptitude. The performance in these examinations is considered the most suitable parameter for final selection, making it essential for candidates to work diligently and honestly to secure top ranks in competitive examinations. There seems to be no other route to success except for hard work. In most competitive examinations, such as Indian civil services, state civil services, banks, public and private organizations, and other state examinations for different posts, university entrance tests, etc., candidates ability in mathematics and general aptitude is assessed. Numerous coaching institutes have mushroomed all over the country to prepare candidates for these competitive examinations, resulting in exorbitant fees that poor but intelligent students cannot afford. This unequal opportunity makes them feel unfortunate and hopeless, causing them to lose confidence in their ability to pass the examinations. To address this issue, this book, Basics of Mathematics and Aptitude, has been designed in a simple manner to cover most of the important areas of general mathematics, including simplification, average, age calculation, time and work, area, ratio and proportion, HCF and LCM, interest and compound interest, percentage, profit and loss, speed and distance, and boat and stream. This book aims to provide support and guidance to all aspiring young individuals who are preparing for competitive examinations.