Letter Series Completion

• How to treat letters as numbers using their alphabet position (A=1, B=2, ... Z=26) to spot patterns quickly.
• Forward and backward stepping patterns, increasing-gap patterns, and grouped (paired-letter) patterns.
• A quick jot-the-numbers method that avoids alphabet-counting mistakes.

1. Constant forward step — each letter moves the same number of places ahead, e.g. A, C, E, G (+2 each time).
2. Constant backward step — letters move backward by a fixed number of places, e.g. U, S, Q, O (-2 each time).
3. Increasing gap — the step size itself grows, e.g. A, B, D, G (+1, +2, +3).
4. Grouped/paired patterns — pairs of letters shift together, e.g. AB, DE, GH (each pair starts 3 places after the previous pair).

Series: B, D, F, H, ?

Step 1 — convert to numbers: B=2, D=4, F=6, H=8
Step 2 — spot the pattern: +2 each time
Step 3 — next number = 8 + 2 = 10 → letter J

• Losing count of alphabet positions — always write the position number under each letter first.
• Confusing forward and backward direction in descending series.
• Missing that a "gap" pattern is increasing rather than constant.

• Convert K to its alphabet position number.
• What comes next: Z, X, V, T, ?
• What comes next: AB, DE, GH, ?

Open the Practice tab for graded questions on Letter Series Completion.