This hard worksheet asks first graders to reason about measurement, not just name the tools. Part A's four multiple-choice problems include a pencil that is 12 clips next to a 9-clip marker, a book that measures 7 cubes for Sam but 10 clips for Mia, and a ribbon of 8 inches against a string that is 1 foot. Part B follows with five fill-in-the-blank items: adding a 4-inch crayon and a 6-inch marker, doubling a 5-cube shelf, learning that 12 inches equals 1 foot, and explaining why standard units give the same result every time.