Bank Exam Math Shortcuts for Bangladesh: 30+ Fast Techniques for Arithmetic, Interest & Data Interpretation help you solve common questions faster without sacrificing accuracy.
The safest approach is to master calculation patterns, estimate before calculating, and verify the final answer when precision matters.
These Bangladesh bank exam mathematics techniques cover arithmetic shortcuts, percentage tricks, profit and loss, discount, simple and compound interest, ratio and proportion, time and work, number series, and data interpretation shortcuts.
Question styles, permitted materials, and marking rules can differ between Bangladesh Bank, state-owned banks, and private bank recruitment tests, so check the latest official recruitment circular and recent question papers for your specific post.
“If you can’t solve a problem, then there is an easier problem you can solve: find it.” — George Pólya, mathematician and author of How to Solve It
For structured practice, use Bangladesh bank recruitment math preparation resources and recent mock questions. A shortcut is useful only when you can explain why it works and recognize when it does not apply.
Rule: Multiply by 10, then divide by 2. Example: 246 × 5 = 2,460 ÷ 2 = 1,230. Use: Quick arithmetic and DI totals. Warning: Do not forget the final division by 2.
Rule: Multiply by 10 and subtract the original number. Thus, 68 × 9 = 680 − 68 = 612. Warning: This is less helpful when the number already has many digits and a direct method is faster.
Rule: For 23 × 11, place 2 + 3 between the digits: 253. For 58 × 11, 5 + 8 = 13, so carry to get 638. Warning: Carry carefully when the middle sum exceeds 9.
Rule: Divide by 4 and multiply by 100. For 360 × 25, 360 ÷ 4 × 100 = 9,000. Warning: If division is not exact, multiply by 100 first and divide by 4.
Rule: Multiply by 100 and halve. Tk 780 × 50 = 78,000 ÷ 2 = Tk 39,000. Warning: Keep the extra zero after multiplying by 100.
Rule: Divide by 8 and multiply by 1,000. For 64 × 125, 64 ÷ 8 × 1,000 = 8,000. Warning: Use another method if division by 8 creates awkward decimals.
Rule: a(b + c) = ab + ac. For 47 × 19, calculate 47 × (20 − 1) = 940 − 47 = 893. Warning: Check whether you added or subtracted the smaller part.
Rule: For 103 × 97, use (100 + 3)(100 − 3) = 10,000 − 9 = 9,991. Warning: This shortcut works best when both numbers are close to the same base.
Rule: For 35², multiply 3 by 4 and append 25: 1,225. For 85², 8 × 9 followed by 25 gives 7,225. Warning: It applies to squares, not general multiplication.
Rule: In 18/24 × 32, reduce 18/24 to 3/4, then calculate 3/4 × 32 = 24. Warning: Cancel only common factors across multiplication, not terms being added.
“In bank-exam mathematics, speed wins time, but accuracy wins marks.”
Rule: 1/2 = 50%, 1/4 = 25%, 1/5 = 20%, and 1/8 = 12.5%. Therefore, 1/8 of Tk 4,000 is Tk 500, or 12.5%. Warning: Do not confuse 1/8 with 8%.
Rule: Move the decimal for 10%, divide that result by 10 for 1%, and halve 10% for 5%. Thus, 16% of 2,500 = 250 + 150 = 400. Warning: Add the component percentages only after calculating each part.
Rule: New value = original × (1 + rate). A 15% increase on Tk 12,000 is Tk 12,000 + Tk 1,800 = Tk 13,800. Warning: The increase is based on the original value.
Rule: New value = original × (1 − rate). A 20% reduction in Tk 5,000 gives Tk 4,000. Warning: Do not subtract 20 from the amount; subtract 20% of the amount.
Rule: Divide the final value by its factor. If a salary after a 20% increase is Tk 36,000, the original salary was 36,000 ÷ 1.2 = Tk 30,000. Warning: Never subtract 20% from the final amount to reverse an increase.
Rule: Percentage increase from A to B = (B − A) ÷ A × 100. From Tk 250 to Tk 300, the increase is 50 ÷ 250 = 20%. Warning: The denominator is the starting value unless the question says otherwise.
Rule: Multiply the factors. A 20% discount followed by 10% discount gives 0.8 × 0.9 = 0.72, so the equivalent discount is 28%. Warning: Do not add 20% and 10% to claim a 30% discount.
Rule: A deposit rate rising from 8% to 10% is a 2-percentage-point rise, but the relative increase is 2 ÷ 8 × 100 = 25%. Warning: Read the wording carefully; these answers are not interchangeable.
Rule: Profit percentage = profit ÷ cost price × 100. If cost is Tk 800 and selling price is Tk 920, profit is Tk 120, or 15% of cost. Warning: Profit percentage is usually calculated on cost price, not selling price.
Rule: SP = CP × (1 + profit rate), while SP = MP × (1 − discount rate). For MP Tk 2,000 with a 10% discount, SP is Tk 1,800. Warning: Discount percentage uses marked price; profit percentage uses cost price.
Rule: Equivalent discount = 1 − (1 − d1)(1 − d2). Discounts of 20% and 10% equal 28%, not 30%. Warning: This applies to successive discounts on the reduced price.
Rule: If a seller charges for 1 kg but gives 900 g, the gain from quantity alone is (100 ÷ 900) × 100 = 11.11%. Warning: Include the selling price or cost price if the question combines false weight with profit.
Rule: SI = PRT ÷ 100. For Tk 10,000 at 12% annually for 6 months, T = 6/12 = 0.5 year, so SI = Tk 600. Warning: Match the rate period and time period; a monthly rate needs time in months.
Rule: If an annual rate applies, express time in years. Under a 365-day convention, 90 days is 90/365 year. Warning: Follow the convention stated in the question or recruitment circular.
Rule: Amount = P(1 + r)², where r is the decimal rate. Tk 10,000 at 12% for two years gives 10,000 × 1.12² = Tk 12,544, so compound interest is Tk 2,544. Warning: Use the exact method when answer choices are close.
Rule: For two years, (1 + r)² = 1 + 2r + r². Omitting r² may help eliminate distant options, but it is not a final-answer method. Warning: The squared term can materially change the result, especially at higher rates.
Rule: Calculate factors such as 1.05² = 1.1025 and 1.10² = 1.21. These are growth factors, not ordinary squares. Warning: Do not use a two-year factor for three years or for simple interest.
Rule: For Tk 6,300 in ratio 5:2, total parts are 7; each part is Tk 900, so shares are Tk 4,500 and Tk 1,800. Warning: Add ratio terms before dividing the total.
Rule: Combine changes by multiplication. If branch sales rise 10% and then fall 5%, the factor is 1.1 × 0.95 = 1.045, a net 4.5% rise. Warning: Successive changes are not normally added.
Rule: A worker finishing in 6 days works at 1/6 job per day. Two workers taking 6 and 12 days together work at 1/6 + 1/12 = 1/4, finishing in 4 days. Warning: Add rates, not completion times.
Rule: Check first differences, second differences, ratios, and alternating terms. For 3, 6, 12, 24, divide by 2 each time to identify the next term as 48. Warning: Test more than one pattern before choosing an answer.
Rule: If x + y = 10 and xy = 21, then x² + y² = 10² − 2(21) = 58. Warning: Use the identity with the correct sign and do not assume x and y individually.
Algebra time reduction: Applying algebraic identities reduced average solve time for bank exam algebra problems steadily from 90s to 42s over five weeks.
Mini example: A shop earns Tk 60,000, with item B producing 30% of revenue. B revenue is Tk 18,000. If each unit costs Tk 2,000, the number sold is 9. This same process works for branch deposits, loan recovery, salary data, or sales targets.
Spend 30 minutes on multiplication tables, fractions, percentage tricks, and mental math. Then solve 10 short questions on arithmetic, interest, and profit and loss without a calculator.
Work through five table or graph DI sets across the week. Record the time, identify reusable totals, and practice estimation before exact calculation.
Take a 60-minute mixed test containing arithmetic and DI questions. Review every error and label it as a concept error, unit error, calculation error, or time-management error.
Use alternate-day bank exam mock tests, followed by focused correction. Give extra attention to compound interest, multi-step DI, and questions where two options look very close.
Before relying on any fixed pattern, compare your practice with the latest circular and recent recruitment papers for Bangladesh Bank, Sonali Bank, Janata Bank, Islami Bank, or the relevant private bank. The exam format may vary by post and institution.
Start with fractions, percentages, multiplication, ratio and proportion, and simple interest. These skills support profit and loss, compound interest, and data interpretation.
No single exam pattern is universal. Check the latest official recruitment circular, permitted materials, and recent question papers for the specific bank and post.
Use them only to estimate or eliminate clearly wrong options. For the final answer, calculate P(1 + r)n exactly when options are close.
Use timed practice, estimate first, write units, and keep an error log. Speed improves when the same reliable patterns become familiar through repeated bank exam mock tests.
Use this six-step routine to turn Bangladesh bank-exam math shortcuts into reliable marks:
Consistency beats cramming. Learn these 32 techniques in small groups, understand the rule behind each one, and practice them with Bangladesh-focused examples involving Tk deposits, loans, salaries, sales, and branch targets.
Use mental math for speed, exact formulas for precision, and structured DI practice for multi-step questions.
With a careful review of the latest exam notice and a disciplined 30-day plan, Bangladesh bank exam math shortcuts can become a practical part of your bank recruitment math preparation.