Concept 3 of 6
Alphabet Series: The Next Letter
Today's big idea
Count how many places you jump between letters, then jump that far again.
Starting from A each time is slow; count on from the letter you are already at.
How it works
👀 What's going on?
Try naming the letter three places after P without singing the whole alphabet first. Most people stall for a second, and that little wobble is what makes letter questions feel tricky.
💡 Here's the trick
Look at the letters above. Each one sits two places on from the one before, so the arcs all read +2. An alphabet series has one step size, just as a number series has one gap. Find the step and you can walk straight to the answer.
🪄 How to do it
- 1.Write out the letters from the series above with the alphabet under them.
- 2.Count the places you jump from one letter to the next.
- 3.Walk that same jump on from the last letter given.
✍️ Try it
- 1.What letter comes next in K, L, M, N, ?
- 2.What letter comes next in Q, S, U, W, ?
Series 1 steps on by one letter each time, so after N comes O. Series 2 skips a letter each time: Q, (R), S, (T), U, (V), W. Skip X and you land on Y.
⚠️ Watch out
You might be thinking the safest move is to start at A and recite. Try that on Q, S, U, W and notice that you plough through 16 letters before the series even begins. Count from the letter you are on instead. Q to S is two places, and that is all you need. One more thing: a series stops at Z, so a step that runs past Z means you read the step wrong.
🌟 Why this matters
Letter order is how a dictionary finds a word, how a register lists a class, and how a library shelves its books. Knowing the step also cracks simple codes, where every letter shifts by the same amount. You will use it long after the alphabet stops feeling new.
Exam tip: Alphabet series appear in the reasoning section of nearly every Class 3 paper, usually as the friendliest item there.
Watch me solve one
Quanta solves it
“Watch how I think through one of these — then you try.”
THE PROBLEM
“Find the next letter: C, G, K, O, ?”
- 1
Count the step between letters
C → G skips three, so +4. G → K is +4. K → O is +4.
- 2
Confirm the step
Every step is +4 — skip three letters each time.
- 3
Walk +4 from O
O → (skip P, Q, R) → S
- 4
Answer ✓
Next = S
Now you try one — same steps, different story 👇
See it in action
⚡ Time to play!
Each hop is +2 along the alphabet. Hop to the next letter.
ALPHABET SERIES · ROUND 1 OF 3
A, C, E, G, ?
Quick check
✅ VERIFICATION
In the series F, I, L, O the next letter is R. What step is the series using?
⚡ Finish the activity above first to answer.
Keep going!
Up next: Letter + Number Pairs
Two rules, two tracks, then combine.