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How to Solve Letter Series Puzzles

Letter series puzzles use alphabet positions to form patterns. Compare each move, then check for a fixed step, alternating steps, or pairs moving in opposite directions. Writing out the alphabet can help you track them.

  1. Puzzle 1

    Which letters come next?

    1. K
    2. L
    3. M
    4. N
    5. O
    6. ?
    Q
    O
    P
    R
    L
    S
    Show the answer

    Answer: C

    Why. Take the letters as positions in the alphabet: K is 11, L is 12, M is 13, N is 14, O is 15. Each step goes 1 place forward. Next: 15 + 1 = 16, which is P.

  2. Puzzle 2

    Which letters come next?

    1. J
    2. K
    3. L
    4. M
    5. N
    6. O
    7. ?
    Q
    K
    R
    P
    O
    N
    Show the answer

    Answer: D

    Why. Take the letters as positions in the alphabet: J is 10, K is 11, L is 12, M is 13, N is 14, O is 15. Each step goes 1 place forward. Next: 15 + 1 = 16, which is P.

  3. Puzzle 3

    Which letters come next?

    1. Y
    2. U
    3. Q
    4. M
    5. I
    6. ?
    C
    G
    F
    D
    E
    A
    Show the answer

    Answer: E

    Why. Take the letters as positions in the alphabet: Y is 25, U is 21, Q is 17, M is 13, I is 9. Each step goes 4 places back. Next: 9 − 4 = 5, which is E.

  4. Puzzle 4

    Which letters come next?

    1. Z
    2. V
    3. R
    4. N
    5. J
    6. ?
    A
    G
    E
    B
    K
    F
    Show the answer

    Answer: F

    Why. Take the letters as positions in the alphabet: Z is 26, V is 22, R is 18, N is 14, J is 10. Each step goes 4 places back. Next: 10 − 4 = 6, which is F.

  5. Puzzle 5

    Which letters come next?

    1. I
    2. J
    3. L
    4. M
    5. O
    6. P
    7. R
    8. ?
    S
    T
    N
    Q
    W
    U
    Show the answer

    Answer: A

    Why. As positions: I is 9, J is 10, L is 12, M is 13, O is 15, P is 16, R is 18. The steps alternate +1, +2, +1, +2... The next step is +1: 18 +1 gives 19, which is S.

  6. Puzzle 6

    Which letters come next?

    1. C
    2. D
    3. F
    4. G
    5. I
    6. J
    7. L
    8. ?
    R
    M
    N
    O
    P
    L
    Show the answer

    Answer: B

    Why. As positions: C is 3, D is 4, F is 6, G is 7, I is 9, J is 10, L is 12. The steps alternate +1, +2, +1, +2... The next step is +1: 12 +1 gives 13, which is M.

  7. Puzzle 7

    Which letters come next?

    1. GR
    2. IP
    3. KN
    4. ML
    5. ?
    OL
    OI
    OJ
    KJ
    QH
    LJ
    Show the answer

    Answer: C

    Why. Look at the first letters and the second letters separately. First letters: G is 7, I is 9, K is 11, M is 13, each 2 forward. Second letters: R is 18, P is 16, N is 14, L is 12, each 2 back. Next pair: O (15) and J (10), so OJ.

  8. Puzzle 8

    Which letters come next?

    1. MU
    2. OT
    3. QS
    4. SR
    5. UQ
    6. ?
    WR
    XP
    WQ
    WP
    YO
    ZP
    Show the answer

    Answer: D

    Why. Look at the first letters and the second letters separately. First letters: M is 13, O is 15, Q is 17, S is 19, U is 21, each 2 forward. Second letters: U is 21, T is 20, S is 19, R is 18, Q is 17, each 1 back. Next pair: W (23) and P (16), so WP.

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The same kinds of puzzle, against the clock, with a result.

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How can you track letter steps?

To track letter steps, compare each letter with the next and count the places it moves forward or backward in the alphabet. Writing out the alphabet can help you keep your place as you count.

A series may use the same step each time, or it may switch between different steps. Check the full sequence before choosing a rule, since a rule that fits only the first moves may not explain the rest. This page has 8 puzzles with answers and explanations for checking your reasoning.

How do alternating steps and pairs work?

Alternating steps use two different moves in a repeating order. For example, one move might go forward by one place and the next by three; check that the same order continues through the series.

With pairs, the two letters may move in opposite directions. Follow each letter separately, then compare how the gap between them changes. This can help you tell an opposing movement pattern from a repeated step.

What mistakes make letter series harder?

A common trap is settling on a rule before checking every move. Several rules may fit a few letters, so test your idea against the whole sequence and both letters in each pair.

Direction changes can make counting harder, so write each letter and its position on paper and mark the step beside it. Do not assume the alphabet wraps from its end to its beginning unless the puzzle supports that rule. Try more reasoning sets to practice tracking patterns in different puzzle types.

Questions

Should I start counting at A or at the first letter?

Start with the letter shown in the series and count the places to the next letter. You do not need to begin at A each time. Writing out the alphabet can make backward moves easier to check.

What should I do if more than one pattern seems possible?

Test each possible rule against every move, including both letters in any pair. Choose the rule that explains the full sequence consistently. If the puzzle provides an explanation, compare it with your reasoning after you have tried the pattern.

Do letter series puzzles test vocabulary?

They use alphabet positions rather than word meanings. Letter series are one kind of reasoning practice; the free IQClock test includes other puzzle formats and does not print an IQ score.