Free SSC Chapter-Wise Notes

Types of Numbers

• Natural Numbers: 1, 2, 3… | Whole: 0, 1, 2… | Integers: …−2,−1,0,1,2…
• Rational: p/q form (q≠0) | Irrational: √2, π — non-terminating, non-repeating
• Prime: divisible only by 1 and itself; only even prime = 2

Divisibility Rules

BODMAS Rule

• Brackets → Order (powers/roots) → Division → Multiplication → Addition → Subtraction
• For approximation: round to nearest easy number, compute, then adjust

Fraction ↔ Decimal ↔ Percent

Core Formulas

• % = (Value / Total) × 100
• % Change = [(New − Old) / Old] × 100
• Successive % change A then B → Net = A + B + AB/100
• x% of y = y% of x (cross trick)

Key Formulas

• Profit = SP − CP | Loss = CP − SP
• Profit% = (Profit / CP) × 100 | SP = CP × (100 + P%) / 100
• Successive Discounts x% & y%: Net = x + y − xy/100
• Dishonest dealer gain% = (Error / True weight − Error) × 100

Formula

• SI = (P × R × T) / 100 | Amount = P + SI
• P = (SI × 100) / (R × T) | R = (SI × 100) / (P × T)
• Money doubles in SI → T = 100/R years

Formulas

• A = P × (1 + R/100)ⁿ | CI = A − P
• Half-yearly: Rate = R/2, Time = 2n | Quarterly: Rate = R/4, Time = 4n
• CI − SI (2 yrs) = P × (R/100)² | CI − SI (3 yrs) = P(R/100)²(3 + R/100)

Key Rules

• a:b = c:d → ad = bc (cross-multiplication / componendo-dividendo)
• Duplicate ratio of a:b = a²:b² | Sub-duplicate = √a:√b
• Mean proportional of a & b = √(ab) | Third proportional of a,b = b²/a
• Compounded ratio of a:b and c:d = ac:bd

Profit Sharing

• Simple Partnership: Profit ∝ Capital (equal time)
• Compound Partnership: Profit ∝ Capital × Time
• A invests ₹P₁ for t₁, B invests ₹P₂ for t₂ → Ratio = P₁t₁ : P₂t₂

Formulas

• Average = Sum / Count
• Avg of first n naturals = (n+1)/2 | First n even = n+1 | First n odd = n
• If a new member joins and average changes by x → new sum = new count × new avg
• Weighted average = (w₁a₁ + w₂a₂) / (w₁ + w₂)

Alligation Rule

• Ratio = (Dearer − Mean) : (Mean − Cheaper)
• Repeated withdrawal & replacement: Final conc. = C × (1 − x/V)ⁿ

Key Concepts

• A completes in n days → 1-day work = 1/n
• A + B together: T = AB / (A+B)
• Efficiency method: Total work = LCM of all days; find units/day per person
• M₁D₁H₁/W₁ = M₂D₂H₂/W₂ (work equivalence formula)

Rules

• Inlet pipe fills in x hrs → rate = +1/x | Outlet empties in y hrs → rate = −1/y
• Net rate when both open = 1/x − 1/y | Time to fill = xy/(y−x)
• With leak: Time = FL/(L−F) where F = fill time, L = leak empty time

Formulas

• Speed = Distance / Time | 1 km/h = 5/18 m/s | 1 m/s = 3.6 km/h
• Average speed (equal distance) = 2xy/(x+y)
• Relative speed: same direction = |S₁−S₂|; opposite = S₁+S₂

Trains

• Cross a pole: Time = Train length / Speed
• Cross a platform: Time = (Train + Platform length) / Speed

Key Formulas

• Downstream speed (D) = Boat speed (B) + Stream speed (S)
• Upstream speed (U) = B − S
• B = (D + U) / 2 | S = (D − U) / 2
• Time downstream vs upstream: t₁/t₂ = U/D (inverse ratio)

Must-Know Identities

• (a+b)² = a² + 2ab + b² | (a−b)² = a² − 2ab + b²
• a² − b² = (a+b)(a−b)
• (a+b)³ = a³ + 3a²b + 3ab² + b³
• a³ + b³ = (a+b)(a² − ab + b²) | a³ − b³ = (a−b)(a² + ab + b²)
• If a + b + c = 0 → a³ + b³ + c³ = 3abc

Methods to Solve

• Substitution: Express one variable in terms of other, substitute
• Elimination: Multiply equations to match coefficients, then add/subtract
• Cross-multiplication: For a₁x+b₁y=c₁ and a₂x+b₂y=c₂: x = (b₁c₂−b₂c₁)/(a₁b₂−a₂b₁)

ax² + bx + c = 0

• Roots: x = [−b ± √(b²−4ac)] / 2a
• Sum of roots = −b/a | Product of roots = c/a
• Discriminant D = b²−4ac: D>0 → real distinct; D=0 → equal; D<0 → imaginary

Key Angle Pairs

• Complementary = 90° | Supplementary = 180° | Vertically opposite = equal
• Corresponding angles (parallel lines + transversal) = equal
• Alternate interior angles = equal | Co-interior (same-side) = supplementary

Important Properties

• Sum of angles = 180° | Exterior angle = sum of two non-adjacent interior angles
• Pythagoras: a² + b² = c² (right triangle) | Common triples: 3-4-5, 5-12-13, 8-15-17
• Equilateral triangle area = (√3/4)a² | Altitude = (√3/2)a

Similarity & Congruence

• Similar triangles: AA, SAS, SSS similarity criteria
• Ratio of areas of similar triangles = (ratio of sides)²
• Mid-point theorem: line joining midpoints of two sides is parallel to third and half its length

Key Theorems

• Angle in semicircle = 90° (Thales' theorem)
• Angles in same segment = equal
• Angle at centre = 2 × angle at circumference (same arc)
• Tangent ⊥ radius at point of contact
• Two tangents from external point = equal length

Formulas

• Area = πr² | Circumference = 2πr | Arc length = (θ/360) × 2πr
• Sector area = (θ/360) × πr²

Ratios (SOH-CAH-TOA)

• sin θ = P/H | cos θ = B/H | tan θ = P/B
• cosec θ = 1/sin | sec θ = 1/cos | cot θ = 1/tan

Fundamental Identities

• sin²θ + cos²θ = 1
• 1 + tan²θ = sec²θ → sec²θ − tan²θ = 1
• 1 + cot²θ = cosec²θ → cosec²θ − cot²θ = 1

Complementary Angles

• sin(90°−θ) = cosθ | cos(90°−θ) = sinθ | tan(90°−θ) = cotθ

Concepts

• Angle of Elevation: angle formed looking upward from horizontal to object
• Angle of Depression: angle formed looking downward from horizontal
• tan θ = Height / Base → Height = Base × tan θ

General Strategy

• Read all headings and units before solving any question
• Identify the unit (₹ crore, thousands, %) upfront to avoid scaling errors

Type-wise Tips

• Bar Graph: Compare bar heights visually before calculating
• Pie Chart: Value = (Angle/360°) × Total or (% /100) × Total
• Line Graph: Focus on slope direction (increasing/decreasing trends)
• Table: Row totals and column totals — verify given totals before trusting values

Types

• Word Analogy: Doctor : Hospital :: Teacher : School (place of work)
• Number Analogy: 4 : 16 :: 5 : 25 (squares)
• Letter Analogy: AB : DC :: EF : HG (reverse adjacent pair)

Types

• Word classification: category (animals, fruits, metals), usage, properties
• Number classification: odd/even, prime, square, cube — identify the outlier
• Letter classification: number of letters, vowel pattern, position sum

EJOTY Trick

Every 5th letter: E=5, J=10, O=15, T=20, Y=25 — use as anchors to find positions quickly.

Types of Coding

• Letter shift: +3 → A=D, B=E, C=F
• Skip coding: Skip 1 → A→C, B→D; Skip 2 → A→D
• Word coding: Each word replaced by another given word
• Number coding: Letters replaced by numbers per rule
• Reverse coding (ATBASH): A=Z, B=Y, C=X…

Common Patterns

• Arithmetic (AP): constant difference → 2, 5, 8, 11 (+3)
• Geometric (GP): constant ratio → 2, 6, 18, 54 (×3)
• Squares/Cubes: 1, 4, 9, 16, 25 or 1, 8, 27, 64
• Difference of differences (2nd order AP): 1, 3, 7, 13, 21 (diff: 2,4,6,8)
• Mixed: Fibonacci-like, alternating, prime series

Key Concepts

• Write A–Z with positions 1–26 and reverse Z–A with 1–26 for quick lookup
• Opposite letter pairs (sum = 27): A↔Z, B↔Y, C↔X, D↔W…
• Common patterns: skip 1, skip 2, reverse order, alternating pairs

Strategy

• Draw a family tree immediately; use M/F labels for gender clarity
• Start from reference person, work outward step by step

Key Tips

• Always draw a map; fix starting point, mark North upward
• Right turn (clockwise): N→E→S→W→N
• Left turn (anti-clockwise): N→W→S→E→N
• Final displacement (straight-line distance) = Pythagoras theorem

Formula

• Position from left + Position from right = Total + 1
• Minimum total when two persons swap: find the overlap or gap

Venn Diagram Rules

• All A are B + All B are C → All A are C ✅
• No A are B + All B are C → No A are C ✅
• Some A are B + Some B are C → No definite conclusion ❌
• "Definitely" = true in ALL possible diagrams | "Possibility" = true in at least one

Formula

• n(A∪B) = n(A) + n(B) − n(A∩B)
• n(A∪B∪C) = n(A)+n(B)+n(C) − n(A∩B) − n(B∩C) − n(A∩C) + n(A∩B∩C)

Rules

• Conclusion must follow directly from the statement — no external assumptions
• Broad/general conclusions from specific statements = NOT valid
• Comparative conclusions need comparative data in the statement

Rules

• Vertical mirror (left-right flip): Left ↔ Right, Top/Bottom unchanged
• Horizontal mirror (top-bottom flip): Top ↔ Bottom, Left/Right unchanged
• Letters unchanged in vertical mirror: A, H, I, M, O, T, U, V, W, X, Y

Rules

• Water image = horizontal flip (Top ↔ Bottom, Left/Right unchanged)
• Letters unchanged in water image: B, C, D, E, H, I, K, O, X
• Combination: Mirror + Water image = 180° rotation of original

Strategy

• Mentally "unfold" the paper step by step from last fold to first
• Holes made after folding appear symmetrically on both layers when unfolded
• Fold axis = line of symmetry; holes mirror across each fold axis

Approach

• Track fold lines carefully — cuts on folded paper create symmetric cuts when opened
• Number of pieces from n straight cuts through folded paper can increase exponentially
• Always unfold mentally from last fold backward

Strategy

• Look for the given small figure hidden inside the larger complex figure
• Match line count, angles, and relative proportions — not just general shape
• The embedded figure must use the same lines as the complex figure (no extra lines)

Types & Method

• Counting triangles: Count small + medium + large; use formula for standard grids
• Counting squares/rectangles: For n×n grid: squares = n²+(n−1)²+…+1² | rectangles = ⁿ⁺¹C₂ × ⁿ⁺¹C₂
• Counting straight lines: identify all possible paths along grid lines

Pattern Types

• Rotation: figure rotated 45°, 90°, 180° in each step
• Size change: figure grows or shrinks progressively
• Addition/deletion: elements added or removed each step
• Movement: shading or elements move along a fixed path

Types of Nouns

• Proper: Names of specific people/places (Ram, India)
• Common: General names (boy, city)
• Collective: Group names (team, herd, flock)
• Abstract: Ideas/feelings (love, freedom, courage)
• Material: Substances (gold, water, wood)

Types & Rules

• Personal: I/me, he/him, she/her, they/them, we/us, you
• Reflexive: myself, himself, themselves — used when subject = object
• Everyone/someone/nobody → singular pronoun (his/her, NOT their in formal English)
• Between two → each other | Among 3+ → one another

Types

• Transitive: Requires an object (She reads a book)
• Intransitive: No object needed (He sleeps)
• Auxiliary: is/am/are/was/were/has/have/do/will/shall/can/may/must
• Modal: can, could, may, might, shall, should, will, would, must, ought to

Degrees of Comparison

Types

• Manner (how): quickly, carefully | Place (where): here, there, away
• Time (when): now, soon, yesterday | Frequency: always, never, often
• Degree: very, quite, almost, enough (always placed before the word it modifies)

Common Rules

• at (point): at noon, at the corner | in (enclosed space/period): in March, in India
• on (surface/day): on Monday, on the table | by (not later than): by 5 PM
• since (point of time): since 2010 | for (duration): for 3 years
• between (two) vs among (three or more)

Types & Pairs

• Coordinating: FANBOYS — For, And, Nor, But, Or, Yet, So
• Correlative pairs: either…or | neither…nor | both…and | not only…but also | whether…or
• Subordinating: although, because, since, unless, until, if, when, while

Usage Rules

• A: before consonant sound (a university, a one-way)
• An: before vowel sound (an hour, an MBA, an honest man)
• The: specific/known noun, superlatives, unique things (the Sun), rivers, oceans, mountain ranges
• No article: languages, meals, sports, proper nouns (generally)

Key Rules

• Each / every / either / neither → always singular verb
• "A number of" → plural verb | "The number of" → singular verb
• Neither…nor / Either…or → verb agrees with the nearer subject
• Collective nouns (team, jury) → singular when acting as one; plural when divided

Conversion Rule

• Object of active → Subject of passive
• Passive verb = is/am/are/was/were/be/been/being + V3
• Subject of active → "by + object" (optional if unknown/obvious)

Tense Backshift

Strategy

• Learn word roots: "bene" (good), "mal" (bad), "dict" (say), "rupt" (break), "port" (carry)
• Use context of surrounding sentence to infer meaning
• Eliminate options that are clearly opposite or unrelated first

Common Misspellings

Common Error Areas

• Subject-Verb agreement (Each, neither, either → singular)
• Tense consistency within a sentence
• Misuse of articles and prepositions
• Dangling modifiers and parallelism
• Double negatives ("didn't do nothing" ❌)
• Comparative errors ("more better" ❌)

Approach

• Read the underlined part and identify what sounds wrong (tense, grammar, word choice)
• Check each option against the full sentence context
• "No improvement" is a valid answer — don't change correct sentences

Approach

• Single blank: check grammar fit first (noun/verb/adj/adv), then meaning
• Double blank: eliminate options where either word fails — both must fit
• Connector words signal contrast (although, however) or cause (because, since)

Strategy

• Read the entire passage once for overall context before filling any blank
• Check grammatical category needed: noun/verb/adjective/adverb
• Eliminate options that break the logical/grammatical flow

Strategy

• Read questions first, then skim passage for relevant paragraphs
• Main idea → check first and last paragraphs
• Inference questions → answer must be implied, not directly stated
• Tone/attitude → look for positive/negative/neutral language

Strategy

• Opening sentence: introduces topic, no pronoun reference back, no connector word at start
• Closing sentence: concluding tone (hence, thus, therefore), no further follow-up needed
• Look for pronoun–noun pairs and connector words (however, moreover, therefore)
• Use elimination to narrow down answer choices

Key Periods

• Indus Valley Civilisation: 2600–1900 BCE; major cities: Harappa, Mohenjo-daro, Lothal
• Vedic Age: Rigveda — oldest; Upanishads, Mahabharata, Ramayana
• Maurya Empire: Chandragupta Maurya (founded), Ashoka (greatest ruler); capital Pataliputra
• Gupta Empire: "Golden Age" of India — Chandragupta II; Aryabhata, Kalidasa

Key Dynasties & Events

• Delhi Sultanate (1206–1526): Slave, Khilji, Tughlaq, Sayyid, Lodi dynasties
• Mughal Empire (1526–1707): Babur (founder), Akbar (greatest), Aurangzeb (last powerful)
• Vijayanagara Empire: Hampi; Krishnadevaraya was greatest ruler
• Battle of Panipat: 1st (1526) Babur vs Ibrahim Lodi | 2nd (1556) Akbar vs Hemu | 3rd (1761) Marathas vs Afghans

Key Events

• Battle of Plassey (1757) — British East India Company victory; effective start of British rule
• Sepoy Mutiny / 1857 Revolt — first war of Independence; Mangal Pandey, Rani Laxmibai
• Indian National Congress founded: 1885 (A.O. Hume)
• Partition of Bengal: 1905 (Curzon) — sparked Swadeshi movement
• Montagu-Chelmsford Reforms: 1919 | Government of India Act: 1935

Major Movements

• Non-Cooperation Movement (1920–22): Gandhi; withdrew from British institutions
• Civil Disobedience (1930): Dandi March — Salt Satyagraha; March 12, 1930
• Quit India Movement (1942): "Do or Die" — August 8, 1942
• INA: Subhas Chandra Bose; "Give me blood, I will give you freedom"
• Independence: August 15, 1947 | Constitution adopted: November 26, 1949 | Republic Day: January 26, 1950

Key Concepts

• Layers of Earth: Crust → Mantle → Outer Core (liquid) → Inner Core (solid)
• Plate tectonics: movement of tectonic plates causes earthquakes and volcanic activity
• Climate zones: Tropical, Subtropical, Temperate, Polar
• Atmosphere layers: Troposphere (weather), Stratosphere (ozone), Mesosphere, Thermosphere, Exosphere

Key Facts

• Area: 3.29 million km² (7th largest) | Population: ~1.4 billion (2nd largest)
• Longest river: Ganga | Largest state (area): Rajasthan | Smallest state: Goa
• Highest peak: Kangchenjunga (K2 is in Pakistan-administered territory)
• Major soil types: Alluvial (most fertile), Black (cotton), Red, Laterite, Desert
• Tropic of Cancer passes through: Gujarat, Rajasthan, MP, Chhattisgarh, Jharkhand, WB, Tripura, Mizoram

Quick Facts

• Largest country (area): Russia | Smallest: Vatican City
• Longest river: Nile (Africa) | Amazon (South America — largest by volume)
• Highest mountain: Mt. Everest (8,849 m) — Nepal/China border
• Largest ocean: Pacific | Largest continent: Asia | Smallest: Australia
• Deserts: Sahara (largest hot desert) | Antarctic (largest cold desert)

Key Facts

• Adopted: November 26, 1949 | Enforced: January 26, 1950
• Drafted by: Constituent Assembly (Chair: B.R. Ambedkar)
• Longest written constitution in the world
• Originally: 395 Articles, 8 Schedules | Now: 448 Articles, 12 Schedules, 25 Parts
• Preamble: Sovereign, Socialist, Secular, Democratic Republic

6 Fundamental Rights (Articles 12–35)

• Right to Equality (14–18) | Right to Freedom (19–22)
• Right Against Exploitation (23–24) | Right to Freedom of Religion (25–28)
• Cultural & Educational Rights (29–30) | Right to Constitutional Remedies (32)

Fundamental Duties (Article 51-A)

• Added by 42nd Amendment (1976) — originally 10 duties; 11th added by 86th Amendment (2002)
• Includes: respecting Constitution, national flag & anthem, protecting environment

Parliament

• Bicameral: Lok Sabha (Lower House, max 552) + Rajya Sabha (Upper House, max 250)
• Lok Sabha term: 5 years | Rajya Sabha: permanent; 1/3 retire every 2 years
• Money Bill can only be introduced in Lok Sabha

Judiciary

• Supreme Court: highest court; original + appellate + advisory jurisdiction
• Chief Justice of India appointed by President
• High Courts at state level | District Courts at district level

Key Concepts

• GDP: Gross Domestic Product — total value of goods/services in a country in a year
• GNP: GDP + Net factor income from abroad
• Inflation: CPI measures retail inflation | WPI measures wholesale inflation
• Fiscal Deficit: Total expenditure − Total receipts (excl. borrowings)
• Current Account Deficit: Imports of goods+services > Exports

• RBI: established 1935; nationalized 1949; HQ Mumbai; Governor heads RBI
• Repo Rate: RBI lends to banks | Reverse Repo: banks park money with RBI
• CRR: cash reserve kept with RBI | SLR: investment in govt securities
• NEFT (batch) | RTGS (real-time, min ₹2L) | IMPS (24×7) | UPI (instant)

Union Budget

• Presented by Finance Minister | Article 112 (Annual Financial Statement)
• Revenue Budget: Revenue receipts + Revenue expenditure
• Capital Budget: Capital receipts + Capital expenditure (assets/liabilities)

Economic Survey

• Released before Union Budget by Ministry of Finance (Chief Economic Adviser)
• Covers: GDP growth, inflation, external trade, social sector analysis

Key Topics for SSC

• Newton's Laws: Inertia, F=ma, Action-Reaction
• Light: reflection, refraction, total internal reflection, lenses (convex = converging, concave = diverging)
• Sound: travels fastest in solids; cannot travel in vacuum; speed ≈ 343 m/s in air
• Electricity: Ohm's Law V=IR | Series: R = R₁+R₂ | Parallel: 1/R = 1/R₁ + 1/R₂
• SI units: Force = Newton | Energy = Joule | Power = Watt | Pressure = Pascal

Key Topics for SSC

• Acids: pH < 7; taste sour (HCl, H₂SO₄, HNO₃) | Bases: pH > 7; taste bitter (NaOH)
• pH scale: 0–14; pure water pH = 7 (neutral)
• Important compounds: NaCl (table salt), H₂O (water), CO₂ (carbon dioxide), H₂O₂ (hydrogen peroxide)
• Rusting: Fe + O₂ + H₂O → Fe₂O₃ (iron oxide) — prevented by galvanisation (zinc coating)
• Radioactivity discovered by: Henri Becquerel | Marie Curie (Radium, Polonium)

Key Topics for SSC

• Cell: basic unit of life; discovered by Robert Hooke (1665)
• DNA: Deoxyribonucleic acid — carries genetic information; double helix (Watson & Crick, 1953)
• Vitamins: A (vision), B (metabolism), C (immunity/scurvy), D (bones/rickets), K (clotting)
• Blood groups: A, B, AB (universal recipient), O (universal donor)
• Diseases: Malaria (Plasmodium, mosquito), TB (Mycobacterium), COVID-19 (SARS-CoV-2 virus)

What to Track

• Government schemes and their ministries
• Cabinet reshuffles, new ministers and their portfolios
• State elections and new Chief Ministers
• Important bills passed in Parliament

What to Track

• Heads of international organizations (UN, IMF, World Bank, WTO, WHO)
• India's bilateral and multilateral agreements
• G20, BRICS, SCO, ASEAN summits and outcomes
• Major international conflicts and peace agreements

Sports

• Cricket: ICC tournament results, ICC rankings, Player of the Series awards
• Olympics & Commonwealth Games: Indian medal winners
• Grand Slams (Tennis): Australian Open, French Open, Wimbledon, US Open — winners

Awards

• Bharat Ratna, Padma Vibhushan, Bhushan, Shri (civilian awards)
• Arjuna Award (sport) | Khel Ratna (highest sports honour) | Dronacharya (coaches)
• Nobel Prize: Peace — Oslo; Literature, Science — Stockholm

Definition & Characteristics

• Electronic device: accepts data → processes → produces output
• Key traits: Speed, Accuracy, Storage, Automation, Versatility, Diligence
• IPO Cycle: Input → Process → Output

Number Systems

Types of Computers

• Supercomputer (fastest) | Mainframe | Minicomputer | Microcomputer (Personal Computer)

Common Input Devices

• Keyboard — primary text input device
• Mouse — pointing device; scroll, click, drag
• Scanner — converts physical document to digital image
• Microphone — captures audio input
• Webcam — captures video input
• Barcode Reader / OMR / OCR — specialized input devices
• Touchscreen — both input and output (I/O device)
• Joystick / Gamepad — for gaming/simulation

Common Output Devices

• Monitor (VDU) — visual display unit; soft copy output
• Printer — hard copy output; types: Inkjet, Laser, Dot Matrix, 3D
• Speaker — audio output
• Projector — displays enlarged image on screen
• Plotter — draws precise lines/diagrams (engineering/architecture)

Functions of OS

• Acts as interface between user and hardware
• Process management | Memory management | File management | Device management | Security

Types of OS

• Single-user (Windows) | Multi-user (Linux/Unix) | Real-time (RTOS) | Batch | Distributed

Popular OS

• Desktop: Windows, macOS, Linux | Mobile: Android (Google), iOS (Apple)
• Server: Linux, Windows Server | Embedded: RTOS, Android (IoT)

Key Shortcuts

Key Functions

• =SUM(A1:A10) | =AVERAGE(B1:B5) | =MAX() | =MIN() | =COUNT() | =COUNTA()
• =IF(condition, value_if_true, value_if_false)
• =VLOOKUP(value, table, col_index, [range]) | =HLOOKUP() (horizontal version)
• =CONCATENATE(A1, " ", B1) | =LEN(A1) | =LEFT/RIGHT/MID()

Key Facts

• Max rows: 1,048,576 | Max columns: 16,384 (XFD)
• Extension: .xlsx | Macro-enabled: .xlsm | Template: .xltx

Key Facts

• Extension: .pptx | Older: .ppt | Template: .potx
• Views: Normal, Slide Sorter, Notes Page, Reading View, Slide Show
• F5 = Start slide show from beginning | Shift+F5 = Start from current slide
• Transitions: animations between slides | Animations: effects on objects within slides

Common Office Shortcuts

• Ctrl+C/V/X — Copy/Paste/Cut | Ctrl+N — New | Ctrl+O — Open | F12 — Save As

Key Terms

• Internet: Global network of interconnected computers
• WWW: World Wide Web — system of interlinked web pages; invented by Tim Berners-Lee (1989)
• HTTP / HTTPS: Protocol for web; S = Secure (uses SSL/TLS encryption)
• IP Address: Unique identifier for each device; IPv4 = 32-bit; IPv6 = 128-bit
• Browser: Chrome, Firefox, Edge, Safari, Opera
• URL: Uniform Resource Locator — web address format: https://domain.com/path
• Email protocols: SMTP (send) | POP3 / IMAP (receive)

Network Topology

• Star (most common), Bus, Ring, Mesh, Tree, Hybrid

Common Threats

• Virus: Self-replicating malicious program; attaches to files
• Worm: Spreads across networks without user action; no host file needed
• Trojan Horse: Disguises as legitimate software; creates backdoor
• Ransomware: Encrypts data; demands ransom to restore (e.g., WannaCry)
• Spyware: Secretly monitors user activity; steals data
• Phishing: Fraudulent emails/sites to steal login credentials
• DDoS: Distributed Denial of Service — overwhelms server with traffic

Protection Tools

• Antivirus software | Firewall | VPN | Two-Factor Authentication (2FA) | Encryption

Key Concepts

• Database: Organised collection of structured data
• DBMS: Database Management System — software that manages databases (MySQL, Oracle, MS Access, PostgreSQL)
• RDBMS: Relational DBMS — data stored in tables with rows and columns; relationships between tables
• Table: Collection of rows (records/tuples) and columns (fields/attributes)
• Primary Key: Uniquely identifies each record; cannot be NULL or duplicate
• Foreign Key: Column in one table that references the primary key of another table
• Index: Speeds up data retrieval without changing table structure

SQL — Structured Query Language

Important SQL Clauses

• WHERE — filter records | ORDER BY — sort results | GROUP BY — group records
• HAVING — filter after GROUP BY | JOIN — combine rows from two or more tables
• DISTINCT — remove duplicate rows | LIMIT — restrict number of rows returned

Types of Joins

• INNER JOIN: Returns rows matching in both tables
• LEFT JOIN: All rows from left table + matching from right
• RIGHT JOIN: All rows from right table + matching from left
• FULL OUTER JOIN: All rows from both tables

Normalisation

• Process of organising database to reduce redundancy and improve integrity
• 1NF: No repeating groups | 2NF: No partial dependencies | 3NF: No transitive dependencies