Reasoning · Lesson 2

Analogies & Odd One Out

Analogies ask, “Which pair is related in the same way?” Odd-one-out asks, “Which one doesn't belong?” Both are about spotting hidden links — in words, numbers, letters and shapes.

~40 min read8 quick checksTest: 20 questions
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1What is an analogy? The bridge sentence

An analogy compares two pairs that are linked in the same way. It is written with colons:

Lamb : Sheep :: Calf : Cow

Read it as “Lamb is to Sheep as Calf is to Cow”. One colon (:) means “is to”; the double colon (::) means “as”.

LambSheepis the young one ofCalfCowis the young one of:: same bridge ::
The same “bridge” links both pairs: the first word is the young one of the second.

The bridge-sentence method

  1. Look only at the first pair. Make a short, exact sentence that links them: “A bee lives in a hive.”
  2. Put the third word into the same sentence: “A lion lives in a ___.”
  3. Test every option in the blank. Pick the one that fits best (den).
  4. If two options fit, make your sentence more exact and try again.
✏️ Worked example

Pen : Write :: Knife : ? (Eat / Cut / Spoon / Sharp)

  1. Bridge sentence: “A pen is used to write.” (tool → its job)
  2. Same sentence: “A knife is used to ___.”
  3. “Cut” fits. “Sharp” describes a knife but is not its job. Answer: Cut.
⚠️ Olympiad trap: keep the order!

The order inside the first pair must be kept in the second pair. In Calf : Cow :: Kitten : ? the answer is Cat (young → adult). When a question asks you to “choose the pair related like Calf : Cow”, the option Cat : Kitten is wrong — the words are right, but the order is adult → young, which is backwards.

2Types of word analogies

Most olympiad analogies use one of these relationships. When you can name the type, the answer comes quickly.

TypeExamples
Worker : ToolCarpenter : Saw · Tailor : Needle · Surgeon : Scalpel · Painter : Brush · Farmer : Plough · Woodcutter : Axe · Mason : Trowel · Doctor : Stethoscope
Worker : WorkplaceDoctor : Hospital · Teacher : School · Judge : Court · Chef : Kitchen · Pilot : Cockpit · Scientist : Laboratory · Mechanic : Garage · Actor : Stage
Animal : Young oneCow : Calf · Horse : Foal · Sheep : Lamb · Lion : Cub · Dog : Puppy · Cat : Kitten · Goat : Kid · Duck : Duckling · Frog : Tadpole · Deer : Fawn · Kangaroo : Joey · Hen : Chick
Animal : HomeBird : Nest · Bee : Hive · Lion : Den · Horse : Stable · Dog : Kennel · Spider : Web · Rabbit : Burrow · Pig : Sty · Hen : Coop
Animal : SoundDog : Bark · Lion : Roar · Horse : Neigh · Snake : Hiss · Elephant : Trumpet · Frog : Croak · Duck : Quack · Owl : Hoot · Donkey : Bray · Sheep : Bleat
Part : WholePage : Book · Petal : Flower · Wheel : Car · Key : Keyboard · Finger : Hand · Room : House
Product : Raw materialPaper : Wood (trees) · Bread : Flour · Butter : Milk · Glass : Sand · Wool : Sheep · Silk : Silkworm · Jaggery : Sugarcane · Cloth : Yarn
Organ : FunctionEye : See · Ear : Hear · Nose : Smell · Tongue : Taste · Lungs : Breathe · Heart : Pump blood
Instrument : What it measuresThermometer : Temperature · Barometer : Air pressure · Speedometer : Speed · Odometer : Distance travelled · Anemometer : Wind speed · Clock : Time · Ruler : Length
Unit : QuantityMetre : Length · Kilogram : Mass · Litre : Capacity · Second : Time · Degree Celsius : Temperature
Country : CapitalIndia : New Delhi · Japan : Tokyo · France : Paris · Nepal : Kathmandu · Bangladesh : Dhaka · Australia : Canberra · Russia : Moscow
Country : CurrencyIndia : Rupee · Japan : Yen · USA : Dollar · United Kingdom : Pound · Bangladesh : Taka · China : Yuan
Male : FemaleKing : Queen · Lion : Lioness · Horse : Mare · Bull : Cow · Nephew : Niece · Hero : Heroine
Individual : GroupSheep : Flock · Cattle : Herd · Bee : Swarm · Fish : School (or Shoal) · Ship : Fleet · Soldier : Army · Flower : Bouquet
Opposites / Same meaningHot : Cold · Rise : Fall · Brave : Cowardly (antonyms) · Big : Large · Begin : Start (synonyms)
Cause : EffectRain : Flood · Drought : Famine · Fire : Smoke · Exercise : Fitness
Remember the “-meter” family by its first part: thermo = heat (thermometer), baro = weight of the air, i.e. pressure (barometer), anemo = wind (anemometer), speedo = speed (speedometer), odo = road or way (odometer, the distance a vehicle has travelled).
✏️ Worked example

Butter : Milk :: Paper : ? (Book / Pulp / Pen / Write)

  1. Bridge: “Butter is made from milk.” This is Product : Raw material.
  2. “Paper is made from ___.” Book is made of paper (backwards!). Pen and Write are about using paper.
  3. Answer: Pulp (wood pulp).
✏️ Worked example

Speedometer : Speed :: Anemometer : ? (Rain / Wind speed / Height / Heat)

  1. Bridge: “A speedometer measures speed.” Instrument : What it measures.
  2. An anemometer (the spinning cups on weather stations) measures wind speed.
✏️ Worked example (two bridges fit)

Doctor : Stethoscope :: Carpenter : ? (Workshop / Saw / Wood / Chair)

  1. First bridge: “A doctor works with a stethoscope.” Hmm — a carpenter also “works with” wood.
  2. Make it exact: “A stethoscope is a tool the doctor uses.” Wood is a material, not a tool; a workshop is a place; a chair is a product.
  3. Answer: Saw.
⚠️ Olympiad trap

Setters love to put a word from the same topic but the wrong relationship in the options. For Bird : Nest :: Horse : ? you might see “Foal” (young one of horse) and “Neigh” (sound). Only Stable is the home. Also: Australia's capital is Canberra, not Sydney!

Kangaroo : Joey :: Frog : ?

  1. Tadpole
  2. Cub
  3. Kid
  4. Calf
A joey is the young one of a kangaroo. The young one of a frog is a tadpole. (Cub = lion or bear, Kid = goat, Calf = cow.)

Farmer : Plough :: Woodcutter : ?

  1. Needle
  2. Axe
  3. Brush
  4. Trowel
Worker : Tool. A woodcutter uses an axe. Needle is a tailor's tool, brush a painter's, trowel a mason's.

Thermometer : Temperature :: Barometer : ?

  1. Humidity
  2. Wind speed
  3. Air pressure
  4. Rainfall
A barometer measures air (atmospheric) pressure. Wind speed is measured by an anemometer.

3Number analogies

In a number analogy, find the rule that changes the first number into the second, then use the same rule on the third number. Think of a machine: a number goes in, a new number comes out.

× itselfthen + 1417637982
One rule works for every pair: multiply the number by itself, then add 1. So 9 becomes 9 × 9 + 1 = 82.

Rules to try, in order

✏️ Worked example (why you need two pairs)

The same rule turns 2 into 7 and 4 into 13. What does 6 become?

  1. Try “square + 3” on the first pair: 2 × 2 + 3 = 7 ✔. On the second pair: 4 × 4 + 3 = 19 ✘. Rejected!
  2. Try “× 3 + 1”: 2 × 3 + 1 = 7 ✔ and 4 × 3 + 1 = 13 ✔. This rule fits both.
  3. 6 × 3 + 1 = 19.
✏️ Worked example

3 : 12 :: 5 : ? — and we are told that 4 : 20 follows the same rule.

  1. “× 4” works for 3 → 12 but gives 4 → 16, not 20. ✘
  2. Try “number × next number”: 3 × 4 = 12 ✔, 4 × 5 = 20 ✔.
  3. 5 × 6 = 30.

Words as numbers (A = 1, B = 2, …)

Some analogies turn words into numbers by adding letter positions (use EJOTY from Lesson 1).

✏️ Worked example

Using A = 1, B = 2, … Z = 26: if BAG : 10, then CAB : ?

  1. Check the rule: B (2) + A (1) + G (7) = 10 ✔. The number is the sum of the letter positions.
  2. CAB = C (3) + A (1) + B (2).
  3. Answer: 6.

The same rule turns 4 into 17 and 6 into 37. What does 9 become?

  1. 81
  2. 37
  3. 83
  4. 82
4 × 4 + 1 = 17 and 6 × 6 + 1 = 37, so the rule is “square, then add 1”. 9 × 9 + 1 = 82. (“× 4 + 1” fits 4 → 17 but gives 25 for 6, so it fails.)

4Letter analogies

Change letters into positions, see how each letter moved, and move the new letters the same way.

A1+6GC3+6IE5+6KM13+6SO15+6UQ17+6W::
ACE → GIK: every letter moves 6 places forward. So MOQ → S U W.
✏️ Worked example

ACE : GIK :: MOQ : ?

  1. A → G is +6, C → I is +6, E → K is +6.
  2. M + 6 = S, O + 6 = U, Q + 6 = W.
  3. Answer: SUW.
✏️ Worked example (opposites)

AB : ZY :: CD : ?

  1. A → Z and B → Y: each letter became its opposite letter (sum 27).
  2. Opposite of C is X; opposite of D is W.
  3. Answer: XW.
✏️ Worked example (order changes)

ANT : TNA :: BAT : ?

  1. The letters of ANT are written in reverse: T-N-A.
  2. BAT reversed is TAB.
💡 Tip

Letters in a group don't always move by the same amount. In BCD : CEG the moves are +1, +2, +3. Write each move under each letter before you answer.

BD : FH :: JL : ?

  1. MO
  2. KM
  3. NP
  4. OQ
B → F is +4 and D → H is +4. So J + 4 = N and L + 4 = P: NP.

5Figure analogies

For shapes, ask: what changed from figure 1 to figure 2? Check this list one by one:

?::::ABCD
Figure 1 → Figure 2: the outer and inner shapes swap places. So a triangle holding a circle becomes a circle holding a triangle: option B.
✏️ Worked example (two changes at once)

Look at the figure below. What replaces the question mark?

  1. Change 1: the arrow turns 90° clockwise (up → right).
  2. Change 2: the arrow goes from white to shaded.
  3. Apply both to the left-pointing white arrow: left turned 90° clockwise points up, and it becomes shaded.
  4. Answer: A (shaded, pointing up). B has the right direction but no shading; C and D are shaded but point the wrong way.
?::::ABCD
Up → right is a quarter turn clockwise, and white becomes shaded. Apply both changes to the third figure.
⚠️ Olympiad trap

In figure questions the wrong options usually get one change right and miss the other. After you pick an answer, check it against every change you found.

6Odd one out: words

In classification questions, three items share a property and one does not. Find a group name that fits exactly three.

  1. Say what each item is: Mango (fruit), Apple (fruit)…
  2. Find a group name that fits three of them.
  3. If more than one grouping is possible, choose the deepest, most exact one — science beats looks.
GroupOdd oneWhy
Cardamom, Turmeric, Clove, PotatoPotatoThe others are spices; potato is a vegetable (a tuber).
Guava, Papaya, Brinjal, OrangeBrinjalThe others are fruits; brinjal is cooked as a vegetable.
Sparrow, Crow, Bat, PigeonBatA bat flies but is a mammal; the others are birds.
Whale, Dolphin, Shark, SealSharkA shark is a fish; the others are mammals living in water.
Ostrich, Penguin, Parrot, EmuParrotAll are birds, but only the parrot can fly.
Mercury, Venus, Moon, MarsMoonThe Moon is a satellite; the others are planets.
Knight, Rook, Bishop, SoldierSoldierKnight, rook and bishop are chess pieces.
Sitar, Veena, Violin, ShehnaiShehnaiYou blow a shehnai (wind instrument); the others have strings.
April, June, September, MarchMarchMarch has 31 days; the others have 30.
Litre, Metre, Kilometre, CentimetreLitreLitre measures capacity; the others measure length.
Kettle, Pan, Tawa, SofaSofaSofa is furniture; the others are cooking utensils.
✏️ Worked example

Find the odd one out: Rose, Lotus, Lily, Banyan

  1. Rose, lotus and lily are flowers.
  2. Banyan is a tree.
  3. Answer: Banyan.
⚠️ Olympiad trap: looks vs science

A bat has wings, a whale lives in the sea, a tomato is used like a vegetable. Don't be fooled by how things look or where they live — ask what they really are. Bat and whale are mammals; a tomato is botanically a fruit.

Find the odd one out: Whale, Shark, Dolphin, Bat

  1. Whale
  2. Shark
  3. Dolphin
  4. Bat
Whale, dolphin and bat are mammals (they feed their babies milk). A shark is a fish.

7Odd one out: numbers

Run each number through this property checklist until one number behaves differently.

CheckExample groupOdd one
Even or odd?22, 46, 85, 6885 (odd)
Prime or not?41, 43, 47, 4949 = 7 × 7
Multiple of a number?14, 21, 35, 4545 (not in the 7 table)
Square number?36, 64, 90, 8190
Cube number?8, 27, 36, 6436 (a square, not a cube)
Sum of digits182, 821, 236, 345345 (sum 12; the rest sum to 11)
Digit pattern234, 345, 456, 657657 (digits not in 1-up order)

Prime numbers: know them cold

A prime number has exactly two factors: 1 and itself. 1 is not prime, and 2 is the only even prime.

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100primelooks prime, but is not
The 25 prime numbers up to 100 (shaded). Numbers like 51, 57, 87 and 91 look prime but are not: 51 = 3 × 17, 57 = 3 × 19, 87 = 3 × 29, 91 = 7 × 13.
Remember: “2, 3, 5, 7 — then 11, 13, 17, 19”: there are 4 primes below 10 and 8 primes below 20. Above 5, a prime can only end in 1, 3, 7 or 9 — but not every number ending in those is prime (21, 27, 33, 39, 49, 51…).
💡 Speed trick: the digit-sum test for 3

If the digits of a number add up to a multiple of 3, the number is divisible by 3 — so it is not prime (unless it is 3 itself). 57 → 5 + 7 = 12 → divisible by 3. 39 → 3 + 9 = 12 → divisible by 3.

✏️ Worked example

Find the odd one out: 13, 17, 21, 23

  1. All are odd, so “even/odd” doesn't separate them.
  2. Prime check: 13, 17 and 23 are prime. 21 = 3 × 7.
  3. Answer: 21 (the only composite number).
✏️ Worked example

Find the odd one out: 28, 35, 49, 54

  1. Even/odd: 28 and 54 are even, 35 and 49 are odd — two and two, so that's not it.
  2. Tables: 28 = 7 × 4, 35 = 7 × 5, 49 = 7 × 7, but 54 is not in the 7 table.
  3. Answer: 54.
⚠️ Olympiad trap

If a property splits the group 2 and 2, it is not the rule — keep looking. The correct property always makes exactly one number different.

Find the odd one out: 53, 57, 59, 61

  1. 53
  2. 57
  3. 59
  4. 61
57 = 3 × 19 (digit sum 12 is a multiple of 3), so it is not prime. 53, 59 and 61 are all prime.

8Odd one out: letters and figures

Letter groups

Write the positions and look at the gaps inside each group.

✏️ Worked example

Find the odd one out: DE, PQ, TU, MO

  1. D → E, P → Q, T → U: the letters are neighbours (gap 1).
  2. M → O skips N (gap 2).
  3. Answer: MO.
✏️ Worked example

Find the odd one out: AZ, GT, KP, LN

  1. Check the 27 rule: A + Z = 1 + 26 = 27, G + T = 7 + 20 = 27, K + P = 11 + 16 = 27.
  2. L + N = 12 + 14 = 26. L's real opposite is O.
  3. Answer: LN.

Other letter checks: vowel or consonant (A, E, I, K → K is the only consonant) and forward or backward order (ABC, DEF, HGF, JKL → HGF runs backwards).

Figure groups

ABCD
In A, B and C the number of dots equals the number of sides. D has 6 sides but only 5 dots, so D is the odd one out.

For figures, use the same checklist as figure analogies: sides, dots or lines, shading, curved vs straight, open vs closed, direction.

Find the odd one out: ACE, GIK, MOQ, RTW

  1. ACE
  2. GIK
  3. MOQ
  4. RTW
ACE, GIK and MOQ each skip one letter each time (+2, +2). In RTW, R → T is +2 but T → W is +3.

Explore more

9Quick recap

Flip cards

QuestionHorse : Foal :: Deer : ?
AnswerFawn (young one)
QuestionJudge : Court :: Chef : ?
AnswerKitchen (workplace)
QuestionGlass : Sand :: Jaggery : ?
AnswerSugarcane (raw material)
QuestionSheep : Flock :: Cattle : ?
AnswerHerd (group name)
QuestionIs 91 a prime number?
AnswerNo — 91 = 7 × 13
Question2 : 8 :: 4 : ?
Answer64 (cube: 4 × 4 × 4)
QuestionOdd one out: Tabla, Drum, Mridangam, Flute
AnswerFlute (wind; the others are drums)
QuestionOdd one out: 64, 81, 100, 120
Answer120 (not a square)