Hidden Recall

Show your memory and wisdom in the missing place!

In Hidden Recall, the challenge lies not only in memory, but also in reasoning. On the screen, a series of numbers appeared in turn-but the last number was quietly hidden, leaving only a blank. You must rely on the observation of the preceding digits and combine the potential laws (such as arithmetic, repetition, symmetry or position pattern) to infer the invisible last digit and click the correct answer.
This is not a simple reappearance, but a double game of memory and logic. What you see is not only numbers, but also clues; What you click is not only an option, but also a judgment. With the advance of the level, the sequence becomes longer and the law is more hidden, hiding not only the numbers, but also the truth.