Praneeth, UPSC is a 3 stage selection process involving Prelims, Mains and Interview which tests your personality test. Prelims has 2 Papers namely General Studies and CSAT.

General Studies has Current Events, History of India and Indian National Movement, Indian and World Geography, Indian Polity and Governance, Economic and Social Development, Environmental Ecology, Biodiversity and Climate Change and General Science.

CSAT has Comprehension, Interpersonal skills including communication skills, Logical Reasoning and Analytical ability, Decision making and problem solving, General Mental Ability, Basic numeracy and Data Interpretation.

Analytical Ability, Data Interpretation, Basic Numeracy come under Mathematics section. These are mostly at 12th level which means you need to get the basic right. If you are from a Non Mathematics back ground, you might find it difficult. Arithmetic, Algebra, Geometry and Advanced Mathematics. Practise chapter by chapter and develop mental calculations. Like practise more of basic summation, subtraction, fractions and tables. Numbers, Percentage, Profit and Loss, Simple and Compound Interest, Ratio, Proportionality, Time-Distance, Time-Work, Mixtures, Averages, Partnership, Permutation and Combinations, Probability, Set Theory, Progression and Series, Line, Angles, Triangles, Quadrilaterals, Polygon, Circles, Ares, Volume, Height and Distance, Coordinate Geometry, Basic Trigonometry are few important topics. So you need to stick to NCERT books, get the basic correct and practise the formula. They say that there is no better way to learn Mathematics than to practise Mathematics.