Letter Series
Pattern & Number Series: Letter Series
Letter Series
Letter Series
What you will learn
- How to find the rule connecting letters in a series using their alphabet positions (A=1, B=2, ... Z=26).
- How to handle series made of single letters, pairs of letters, and reverse order letters.
- A simple method: convert letters to numbers, find the number pattern, then convert back to a letter.
Key concepts
Level 1 — Constant skip
Verbal: Each letter is a fixed number of places after the one before it.
Symbolic: A, C, E, G, ? — skip of 2 each time (A=1, C=3, E=5, G=7), so next is I (=9).
| Series | Skip | Next letter |
|---|---|---|
| B, D, F, H | 2 | J |
| A, D, G, J | 3 | M |
| Z, Y, X, W | -1 | V |
Level 2 — Pairs of letters
Verbal: Letters come in pairs (2 consecutive letters), and each new pair starts a fixed number of places after the previous pair started.
Level 3 — Reverse order with alternating skip
Verbal: Letters move backward through the alphabet, and the skip size alternates between two values.
Worked example
Find the next letter: A, D, G, J, ?
Step 1 - Convert to numbers: A=1, D=4, G=7, J=10
Step 2 - Gaps: 3, 3, 3 -> constant skip of 3
Step 3 - Next number = 10 + 3 = 13 -> letter M
Answer: M
Find the next letter: Z, X, V, T, ?
Step 1 - Numbers: Z=26, X=24, V=22, T=20
Step 2 - Each step is -2
Step 3 - Next = 20 - 2 = 18 -> letter R
Answer: R
Common mistakes
| Mistake | Why it happens | Fix |
|---|---|---|
| Miscounting alphabet position | Not knowing A=1...Z=26 | Write the number under each letter |
| Missing reverse direction | Assuming letters always move forward | Check if letters are decreasing |
| Confusing pairs with single letters | Not grouping letters correctly | Group letters in twos if the pattern repeats every 2 |
| Wrapping past Z incorrectly | Adding without checking the limit | Remember the alphabet stops at Z (26) |
Quick check
- What comes after C, F, I, L?
- Convert the letter H to its alphabet number.
- What is the next letter after Y, W, U, S?
- Stretch: Find the next two letters in A, B, D, G, ?, ? (gap grows by 1 each time).
Revision tip: Keep a small A-Z number chart handy while practising letter series.
Open the Practice tab for graded questions on Letter Series.
Key Takeaways (TL;DR)
- What you will learn
- Key concepts
- Worked example
- Common mistakes
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