Master speed calculation techniques for Quantitative Aptitude with fraction-percentage shortcuts, LCM methods, and formula tricks.
Quantitative Aptitude is often the most time-consuming section in banking exams. Long divisions, repeated percentages, and multi-step word problems eat into your 20 minutes faster than any other section. The good news: with the right tricks and mental math techniques, you can dramatically reduce your calculation time and improve accuracy at the same time.
These conversions appear repeatedly in Percentage, Profit & Loss, and SI/CI problems. Learn them like multiplication tables:
When a question asks for 14.28% of 4900, do not multiply; recognise the fraction and compute 4900/7 = 700 instantly. This single habit saves 15-20 seconds on every question in a DI set.
For two successive percentage changes, use: Net% = a + b + ab/100. Example: a 20% increase followed by a 20% decrease gives 20 - 20 - 400/100 = -4%, a net 4% fall. The same formula handles discount-on-discount and population growth problems, eliminating the need for step-by-step calculation.
Always convert Time & Work problems to LCM-based units instead of fractions. If A takes 10 days and B takes 15 days, take total work = LCM(10, 15) = 30 units. A does 3 units/day, B does 2 units/day; together they do 5 units/day, so the job takes 30/5 = 6 days. This integer-based approach is faster and far less error-prone than adding 1/10 and 1/15 under pressure.
For partnership problems, remember one rule: the profit-sharing ratio equals investment multiplied by time for each partner. If A invests ₹5000 for 12 months and B invests ₹6000 for 10 months, the ratio is 60000 : 60000 = 1 : 1, no lengthy working needed. Similarly, when quantities are mixed or divided, write the ratio first and scale it, rather than computing absolute values at every step.
Spend 10 focused minutes every day revising tables up to 25, squares up to 30, and cubes up to 15. Then apply them inside timed topic tests so the recall becomes automatic under exam pressure. Practice in a real exam interface, the way Quiz4Exam topic-wise and sectional tests present questions, so that on-screen calculation feels as natural as paper. A useful weekly drill: pick any 30 random calculations from old DI sets and race to finish them in 10 minutes; beat your own time every week and this section will stop feeling long.
Percentage-fraction equivalents like 1/7 = 14.28% and 1/8 = 12.5%, which let you replace long multiplication with quick division.
Net% = a + b + ab/100. It handles two successive changes, discount-on-discount and growth problems in a single step.
Converting the work to LCM-based integer units avoids adding fractions under pressure, making the calculation faster and far less error-prone.
Spend 10 focused minutes a day on tables, squares and cubes, then apply them in timed topic tests until recall becomes automatic.
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