Ответ:

897 may refer to a year or a number. Here are examples of sentences using both interpretations:

In 897, King Alfred the Great died.

The capacity of the new stadium is 897 seats.

1851 may refer to a year or a number as well:

The Great Exhibition was held in London in 1851.

The price of the painting was £1851.

12th may refer to a position in a series or an ordinal number:

He finished in 12th place in the race.

The 12th chapter of the book was the most interesting.