This report will show which questions students in your class flagged as difficult.
Go to the Reports icon from the dashboard. Use the toggles to select the class exercise red flag report and the class you want to report on. You may also select the exercise level. Then select the Text group (the series) the Text (name of textbook), the chapter and the section you want to report on.
Click Generate. You can create a PDF of this report with the PDF button.