How many problems a day?

Regularity matters more than volume. Ten a day beats a hundred once a week, because mathematics is a habit.

Percentage, ratio and average. Profit and loss, interest, and time-and-work all stand on those three.

Calculating without a calculator is hard — what helps?

Memorise squares, cubes and tables, and learn to work with approximations. Those two habits move most of the arithmetic into your head.

BCS Mathematical Reasoning Preparation

বাংলায় পড়তে চাও? দেখো: বিসিএস গাণিতিক যুক্তি প্রস্তুতি

Mathematical reasoning cannot be learned by reading, only by solving. Ten problems a day beats one weekly session with the book by a distance.

The chapters that keep reappearing

Branch	Chapters
Arithmetic	Percentage, profit and loss, interest, ratio, average
Arithmetic	Time and work, time and distance, boats and streams
Algebra	Identities, factorisation, equations, indices and logarithms
Geometry	Triangles, circles, quadrilaterals, area
Other	Sets, permutations and combinations, probability

The right order to drill in

Taking every chapter at once leaves none of them standing. Take one, understand its rules and identities, work at least thirty problems, and only then move on. At that pace the whole list is done in two months and each chapter actually stays with you.

Take percentage, ratio and average first, because several later chapters stand on them.

Practical ways to save time

Substituting the options is often faster than solving in full.
Working with approximations settles many questions mentally.
Knowing the squares and cubes saves seconds on every problem.
If a problem has not opened in thirty seconds, leave it and move on.

If mathematics is your weak point

The cause is almost always the same — an incomplete foundation. In that case start from the class 8 and 9 mathematics texts rather than a BCS guide. Losing a few weeks to rebuild the base makes every later chapter move faster.