Number series (pattern with binary-like digit toggling): Find the missing term that preserves the 1–0 structure. Given sequence: 11, 10, ?, 100, 1001, 1000, 10001 Observation: terms alternately change the last digit to 0, then append a 1. Choose the correct missing number.

Given data11, 10, ?, 100, 1001, 1000, 10001

Concept/ApproachThe sequence is built by two alternating operations on the digit string: (i) change the last digit to 0, then (ii) append a trailing 1. This keeps a binary-like pattern of 1s and 0s.

Step-by-stepStart: 11Operation (i): 11 → 10 (last digit set to 0)Operation (ii): 10 → 101 (append 1) ← missing termOperation (i): 101 → 100Operation (ii): 100 → 1001Operation (i): 1001 → 1000Operation (ii): 1000 → 10001

Final Answer101