A 2-page printable 2nd grade math worksheet where students act as number grid detectives, filling in missing numbers across rows (+1/-1) and columns (+10/-10) in 2-digit and 3-digit (hundreds) number grid puzzles. Includes a visual clue key, progressive 3x3 and 4x4 puzzles from the 20s through the 900s, high-contrast print-safe grid borders, and a short explanation prompt.