English
Voice Change: BY + Doer — In passive voice, the agent (doer) always follows "by" (e.g., "The ball was caught BY John"). If no doer matters, drop it entirely ("Mistakes were made").
Direct→Indirect: STRPT — Say→Said, Today→That day, Reported (no comma/quotes), Pronoun shift (I→he/she), Tense backshift (present→past, past→past perfect).
One-Word Trick: -cide/-phobia — "Homicide"=killing humans, "Regicide"=king, "Genocide"=race. "Hydrophobia"=fear of water, "Claustrophobia"=enclosed spaces. Remember suffix meanings to decode instantly.
Idioms: Body Parts — "Cost an arm and a leg"=very expensive; "Cold feet"=nervous; "Eye to eye"=agree. Body-part idioms rarely mean literal body actions—think metaphorically.
Synonym/Antonym: Prefix Power — Un-, Dis-, In-, Im- usually negate: Happy↔Unhappy, Agree↔Disagree, Efficient↔Inefficient. Spot prefixes to eliminate wrong options fast.
General Knowledge
BRICS Nations: BISRC — Brazil, India, South Africa, Russia, China. Now add UAE, Egypt, Ethiopia, Iran (expanded 2024) but core five memorize first.
Five-Year Plans: NITI 2015 — Planning Commission abolished Jan 1, 2015, replaced by NITI Aayog. All pre-2017 plans dissolved; now 3-year action plans + 7/15-year vision documents.
GDP vs GNP: "N for Net/National" — GDP=Domestic (within borders); GNP=National (includes income abroad). NNP=GNP minus depreciation. Order: GNP > NDP > NNP.
Fiscal vs Monetary: FM Radio — Fiscal=Finance Ministry (taxes, budgets); Monetary=RBI/Money supply (interest rates, CRR, repo). Different authorities, don't mix.
India Borders: BPMCANM — Bangladesh, Pakistan, Myanmar, China, Afghanistan, Nepal, MyanmarBhutan (7 land neighbors). Mnemonic: "Big People Meet Cool Actors Near Mountains."
Elementary Mathematics
Divisibility by 11: Odd-Even Difference — Subtract sum of odd-position digits from even-position digits. If result divisible by 11 (including 0), number is. Example: 121→(1+1)−2=0, divisible.
Percentage-Fraction Fast: 12.5%=1/8 — Memorize: 12.5%=⅛, 16.67%=⅙, 20%=⅕, 25%=¼, 33.33%=⅓, 50%=½. Convert instantly to simplify calculations without decimal multiplication.
Profit & Loss: SP Formula — SP=CP×(100±Profit%)/100. Plus for profit, minus for loss. Two successive discounts: Net=100−(d₁+d₂−d₁d₂/100).
Average Shortcut: Assumed Mean — Pick middle value as base. Find deviations, average them, add back. Example: 98,99,100,101,102 → base=100, avg of (−2,−1,0,1,2)=0, answer=100.
Linear Equation: Cross-Multiply Instantly — For a₁x+b₁y=c₁, a₂x+b₂y=c₂: x=(b₁c₂−b₂c₁)/(a₁b₂−a₂b₁), y=(c₁a₂−c₂a₁)/(a₁b₂−a₂b₁). Denominator identical; learn the cross-pattern.
Laws of Indices: MADSPM — Multiply→add powers (aᵐ×aⁿ=aᵐ⁺ⁿ), Divide→subtract, (P)ower→multiply (aᵐ)ⁿ=aᵐⁿ. a⁰=1, a⁻ⁿ=1/aⁿ.
Number System: NIRR — Natural(1,2,3...), Integers(...-1,0,1...), Rational(p/q), Real(all including √2). Whole=Natural+0. Each set contains the previous.
Logarithm: log(ab)=log(a)+log(b) — Product→sum, quotient→difference, power→multiply: log(aⁿ)=n·log(a). log₁₀(10)=1, log₁₀(1)=0. Change base: logₐ(b)=log(b)/log(a).