Answer:
The arithmetic sequence in the given series of numbers is 11. The common difference in an arithmetic sequence is the number that is added to each term to get the next term in the sequence. In this case, the common difference is 11, because when we add 11 to the first term, 12, we get 23, which is the second term in the sequence. Similarly, when we add 11 to the second term, 23, we get 34, which is the third term in the sequence, and so on. Therefore, the arithmetic sequence in the given series of numbers is 11