The difficulty of thinking 100 preliminary competition varies from person to person, mainly because everyone's thinking mode and mathematical foundation are different. For those who have been trained in thinking or studied in Olympic Mathematics, they may have a solid mathematical foundation and strong thinking ability, so the difficulty of the preliminary round is relatively low. For those who have not been exposed to these contents, the topic of the preliminary contest may be novel and challenging, and it requires a certain mathematical foundation and thinking ability to successfully complete it.

Everyone's problem-solving methods and ideas may also be different, which also affects the difficulty of the preliminary round.