Analogy and Classification

What is an analogy?

An analogy gives you one pair of words with a link between them. You find another pair with the same link.

It is written like Pen : Write :: Knife : Cut.

What is classification?

You get four items. Three share a property and one does not.

Your job is to spot the odd one out.

What do both skills test?

Both test whether you can see the exact link between words, numbers or letters.

Vague guesses fail. A clear one-line link wins.

How do you find the link?

Make a short sentence from the first pair. For example: A pen is used to write.

Now try the same sentence on the second pair.

Why does this work?

A sentence is exact. It forces you to say what the link really is.

If the sentence fails on an option, drop that option at once.

Can you see it solved?

Doctor : Hospital :: Teacher : ? A doctor works in a hospital.

So a teacher works in a school. The answer is School.

Why this works: the same sentence fits both pairs, so the link is copied exactly.

Can you see a trap solved?

Bird : Nest :: Bee : ? Options: Honey, Hive, Flower, Sting.

A bird lives in a nest. A bee lives in a hive. Honey is a product, not a home.

Why this works: the sentence says lives in, and only Hive fits it.

Which links come up most?

Tool and user, tool and job, part and whole, and cause and effect.

Also opposites, same meaning, and type and group.

Can you give short examples?

Cause and effect: Fire : Smoke. Part and whole: Petal : Flower.

Opposites: Hot : Cold. Type and group: Rose : Flower.

Does the order matter?

Yes. Tool to job is not the same as job to tool.

Keep the order of the first pair in your answer.

Can you see an order trap?

Pen : Write :: ? : ? The link is tool to job.

Knife : Cut fits, because a knife is a tool and cut is its job.

Cut : Knife does not fit, because it turns the pair round.

Why this works: reversing the order changes the link, so the pair no longer matches.

How do you spot the odd one?

Look for what three items share. Try use, type, size, place or shape.

The item that breaks the pattern is the answer.

Can you see it solved?

Apple, Mango, Potato, Banana. Three are fruits that grow on trees.

Potato is a vegetable that grows under the soil. Potato is the odd one.

What if two groupings seem to work?

Try a second property. One of the two groupings will leave a clean 3-and-1 split.

Choose the split that leaves exactly one item out.

Can you see a harder odd one?

Cat, Dog, Cow, Eagle. Three are mammals, and Eagle is a bird.

Another split is pets: Cat, Dog and perhaps Cow. That leaves two out, so it is not clean.

So Eagle is the odd one out.

Why this works: only the mammal split leaves exactly one item behind.

Can you see a number odd one?

16, 25, 36, 40. Three are perfect squares: 4 x 4, 5 x 5 and 6 x 6.

40 is not a square. So 40 is the odd one.

Why this works: the property is square number, and 40 breaks it.

How do number pairs work?

Look for what is done to the first number to get the second. It may be a square, a cube, a double or a sum.

Use the same rule on the third number.

Can you see it solved?

3 : 9 :: 5 : ? The second number is the first number squared.

So the answer is 5 times 5, which is 25.

Why this works: the first pair gives the rule, and the rule gives the missing term.

Can you try a cube?

2 : 8 :: 4 : ? The second number is the first cubed, since 2 x 2 x 2 is 8.

So 4 x 4 x 4 is 64.

Why this works: the rule is cube, and it carries to the next number.

How do letter pairs work?

Count the steps between letters, or check for a reverse order.

The same count or the same reverse applies to the next pair.

Can you see a letter pair solved?

AB : CD :: EF : ? Each letter in AB moves forward 2 places to give CD.

E moves 2 to G. F moves 2 to H. The answer is GH.

Why this works: both letters shift by the same count, so we copy that count.

What mistakes cost marks?

Picking an option that is only loosely related to the third word.

Ignoring the order of the first pair.

How do you stay quick?

Eliminate options that fail your sentence. Rarely will more than one stay.

For odd-one-out, test the most common property first.

How should you practise?

Solve five analogy questions and five odd-one-out questions a day.

Then try the quiz below and read every explanation.