Are you getting an “argument error” on a Ti-89 Titanium? Well, please try executing the “Clear A-Z” command under the “Clean Up” menu (F6) as this will correct the issue.
Note: You can find special characters like “?” under the “CHAR” menu, which is [2nd]+[PLUS] on the TI-89T.
The third submenu, “Punctuation”, has a question mark as the 8th entry.
