Skip to content
QQuanta KidsBy IIT & ISB Alumni
← Back to Codes & Symbols

Concept 8 of 8

Dictionary Order: Find the Position

1

Today's big idea

Collect the deciding letters, sort those, then count to the position asked for.

When words share an opening, compare them at the first letter where they differ.

2

How it works

👀 What's going on?

By Class 5 a paper rarely asks you to write out the whole order. It asks which word lands third, or where a new word would slot in. Sorting the entire list to answer that is slow.

💡 Here's the trick

Only the third letter carries informationTIGERTINTIDETIPTILEshared TIsorted:D1G2L3N4P5third is Lso TILEno need to sort the words

Look at the five words above. They all begin with TI, so the third letters decide everything: G, N, D, P and L. To find the third word you do not need the full order. Count how many third letters come before each one. D and G both beat L, and nothing else does, so TILE sits third.

🪄 How to do it

  1. 1.Find the position where the words actually differ, as the words above share TI.
  2. 2.List just the deciding letters and put those in alphabet order.
  3. 3.Count along to the place the question asks for, rather than writing every word out.

✍️ Try it

Among JUMP, JUG, JUST and JUICE, which is third? Then say where JUNE would slot into that same list.

The deciding letters are M, G, S and I, which order as G, I, M, S. Third along is M, so the answer is JUMP. JUNE decides on N, which sits between M and S, so JUNE lands fourth, pushing JUST to fifth.

⚠️ Watch out

You might be thinking you must sort the list before you can count. You do not. Sorting five words takes four comparisons, while counting the deciding letters takes one pass.
Why it matters: This is how any index works. Finding where a new name belongs in a sorted register is the same one-pass job. It is also how a computer searches a list quickly.
Exam tip: Circle the deciding letter in each word before you count anything.

3

Watch me solve one

Quanta solves it

“Watch how I think through one of these — then you try.”

THE PROBLEM

“Which comes last: TRACK, TRADE, TRAIL, TRAMP?”

  1. 1

    Find where they part

    All four share TRA, so the fourth letters carry everything.

  2. 2

    Collect just those letters

    C, D, I and M, which sort to C, D, I, M.

  3. 3

    Take the last

    M is latest, so TRAMP. The list never had to be written out.

  4. 4

    Answer ✓

    TRAMP

Now you try one — same steps, different story 👇

4

See it in action

⚡ Time to play!

Collect the deciding letters, then count to the position.

POSITION FINDER · ROUND 1 OF 3

JUMP · JUG · JUST · JUICE — which is THIRD?

Step 1 · collect the deciding letters

5

Quick check

✅ VERIFICATION

Which comes LAST in dictionary order: BRAIN, BRAKE, BRAND, BRAVE?

⚡ Finish the activity above first to answer.

Keep going!

You've finished this chapter!

Try the mini-quests →