You may add more questions to a draft quiz after it has been created.  Follow the instructions to edit a draft quiz.  On the edit page, follow these steps to add more questions:

1.Scroll to the bottom of the quiz edit page. The total number of quiz questions and the number/percentage correct needed to pass the quiz are displayed.  Notice that the Total number of questions is a link:

2.Click the number link to the right of Total.

3.Enter the new total number of questions for the quiz:

4.Press Next to continue.

5.Then, enter the new number of correct answers needed to pass the quiz:

6.Press Save. You will be returned to the quiz editing screen.