Eleven Plus — Codes and Logic

Word and letter sequences

Spot the pattern governing a sequence of letters, find the missing term, and explain the rule clearly — the same disciplined, rule-first approach as letter codes, applied to sequences.

Back to Eleven Plus

💡Understand

A letter sequence follows a consistent RULE — often a fixed gap between each letter's position in the alphabet. To solve it, convert each letter to its alphabet position (A=1, B=2...), find the gap between consecutive terms, and check the gap is consistent before predicting the missing term.

“Sequence: B, D, F, H, __? Positions: 2, 4, 6, 8, __. The gap is +2 each time, so the next position is 10, which is J.”

Converting letters to numbers makes the pattern much easier to spot and verify — the gap of +2 is confirmed across THREE consecutive pairs (B→D, D→F, F→H), not just one, before predicting J with confidence.

🔍Spot it

What is the pattern, and what comes next?

Question 1

A, C, E, G, __?

💡 Positions 1, 3, 5, 7, __ — the gap is +2 each time, so the next position is 9, which is I.

Question 2

Z, X, V, T, __?

💡 Positions 26, 24, 22, 20, __ — the gap is -2 each time, so the next position is 18, which is R.

Question 3

B, E, H, K, __?

💡 Positions 2, 5, 8, 11, __ — the gap is +3 each time, so the next position is 14, which is N.

🧠Think about it

Why is converting letters into their numeric alphabet positions a more reliable strategy than trying to 'see' the pattern in the letters directly?

✍️Try it

Find the pattern and the missing term.

C, F, I, L, __?

Question 1

What comes next in the sequence?

💡 Convert to positions: 3, 6, 9, 12, __. Find the consistent gap, then apply it.

📝Practise

Find the pattern and the missing term in each sequence.

Question 1

D, G, J, M, __?

Question 2

Y, W, U, S, __?

Question 3

A, D, G, J, __?

Question 4

In one word, what should you convert letters into to make patterns easier to spot?

💡 It's the core strategy explained in this lesson's Understand section.

Question 5

E, H, K, N, __?

Question 6

Why should you confirm the gap across at least three consecutive pairs before predicting the missing term?

🎯Apply

Read the passage, then answer the questions below.

Exam question: B, E, I, N, __? (Hint: the gap itself is changing, not staying constant.)

Question 1

Convert B, E, I, N to their alphabet positions.

💡 A=1, B=2, C=3... work out each letter's position.

Question 2

What is the pattern in the gaps between each term (2→5→9→14)?

💡 Calculate each individual gap: 5-2, 9-5, 14-9.

Question 3

Following the pattern (gap increasing by 1 each time, next gap +6), what letter comes next after N?

💡 14 + 6 = 20, which alphabet letter is at position 20?

🏆Challenge

Create your own letter sequence using a CHANGING gap pattern (like the Apply example), write out the first four terms, and explain the rule clearly enough for someone else to find the fifth term.

🔄Review

A quick mastery check — 3 questions.

Question 1

A, E, I, M, __?

Question 2

The most reliable way to solve a letter sequence is to...

Question 3

V, S, P, M, __?