Incorrect spelling, explanation: one of the most common endings of ordinal numbers is -th as, for example, it happens with 11th. However, many English users think that the ordinal form of 11 is formed in a similar way to number 1, which is 1st. As a consequence, a popular mistake is to spell 11th as 11st, which is wrong.

Correct spelling, explanation: 11th is a full form of eleventh, which is one of the ordinal numbers in English. 11th has its origin in the Old English form endleofan, which meant ten and one left. The word has remained its original meaning, but it was not until Middle English when 11th started to have a spelling that looked more similar to the version we know today.

Definition of 11th:
1. ordinal number – appears between tenth and twelfth,
Ending the race at the 11th position after so many months of preparation is a rather poor result.

Expressions with 11th:
A few common expressions with 11th include: 11th hour (almost too late), 11th floor, and 11th grade.
He told me about the changes at the 11th hour so I felt really confused at the meeting.
The apartment is on the 11th floor and has an amazing view of the bay.
I teach the 11th grade, which is quite difficult as there are a few kids with serious problems.

Incorrect spelling

Incorrect spelling