How to have a field (with number entered in it, e.g. 12), produce a corresponding number of fields for entry.

How to have a field (with number entered in it, e.g. 12), produce a corresponding number of fields for entry.

I am working on building an educational assessment tool for teachers to share data.

I can't seem to figure out a simple way to do what I want, so I thought I would ask.

If the user enters "12" when prompted for the number of students in his class, I want an action that generates 12 blank fields for student names.  

I hope someone can help