PassCCAT
Letter series

How to solve letter series

Math & Logic

Track how letters shift through the alphabet and supply the next letter or group.

Worked examples

Answers shown

Follow the steps on real items before you practise.

Example 1Difficulty 1

Find the next letter: E, F, G, H, I, ?

Answer: E. Here is why:

  1. Convert the letters to alphabet positions (A=1 … Z=26): E=5, F=6, G=7, H=8, I=9.
  2. The rule is: skip forward 1 letter each time.
  3. That gives position 10, which is J.
Example 2Difficulty 1

Find the next letter: H, K, N, Q, T, ?

Answer: B. Here is why:

  1. Convert the letters to alphabet positions (A=1 … Z=26): H=8, K=11, N=14, Q=17, T=20.
  2. The rule is: skip forward 3 letters each time.
  3. That gives position 23, which is W.
Example 3Difficulty 1

Find the next letter: C, F, I, L, O, ?

Answer: D. Here is why:

  1. Convert the letters to alphabet positions (A=1 … Z=26): C=3, F=6, I=9, L=12, O=15.
  2. The rule is: skip forward 3 letters each time.
  3. That gives position 18, which is R.