Multiple choice general knowledge math & puzzles In the series O, T, T, F, F, S, S, E, __ which is next? P E O N T Reveal answer Fill a bubble to check yourself D Correct answer Explanation The sequence represents the first letter of the English words for numbers: One, Two, Three, Four, Five, Six, Seven, Eight. The next number is Nine, which starts with the letter 'N'. Therefore, 'N' is the correct continuation of the pattern.