Concept:The series follows a constant subtraction pattern where each term is 5 less than the previous term.Explanation:Start with 91. Subtract 5 to get 86.Subtract 5 from 86 to find the missing term: 86 − 5 = 81.Then subtract 5 from 81 to get 76, and from 76 to get 71. The pattern holds.Thus, the missing number is 81.
