卡农钢琴谱简谱:What odd number becomes even when beheaded?

What odd number becomes even when beheaded? What odd number becomes even when beheaded? How do you turn an odd number into even by removing one letter? How do you turn an odd number into even by removing one letter? What number should replace the question mark? What is the port number for UDP? BECO 7号是谁？ From what number can you take half and leave nothing? From what number can you take half and leave nothing? Brain Teasers:What number is like a peacock？