Mathematics: Arithmetic, Algebra and Mensuration
What you must understand
The syllabus is broad but shallow: number system and simplification, percentage, profit-loss, ratio and proportion, averages, time-work and time-speed-distance, simple and compound interest, algebra (identities, linear equations), geometry and mensuration (areas, volumes, Pythagoras), and basic trigonometry and statistics.
Traps to expect
- Percentage change base: a 20% rise then 20% fall does not return to the original value (net −4%).
- Profit-loss on cost price, not selling price, unless stated.
- Time-work problems where workers join or leave mid-way - convert to work-per-day fractions.
- Unit mismatch in mensuration (radius in cm, height in m).
- Approximation items: options are far apart, so estimate rather than compute exactly.
Rule of thumb
For percentage chains, use the multiplier form: successive changes a% and b% give net change = a + b + ab/100.
Worked example
A shopkeeper marks an item 40% above cost and gives a 25% discount. Net multiplier = 1.40 × 0.75 = 1.05, so profit = 5% on cost. Multiplying multipliers is faster and safer than computing prices step by step.
Practice habit
Maintain a formula sheet for mensuration and algebraic identities, and solve 10 simplification questions daily under a timer.