How do you write shall not as a contraction?

"Shall not" doesn't have a common contraction in standard English. It's typically written out.

However, in some dialects or informal speech, you might hear:

* Shan't: This is the most common contraction, though considered somewhat archaic or literary.

* Shouldn't: While this is a contraction of "should not," it can be used informally to substitute for "shall not" in some contexts.