Vary number of questions on a test

I would like for the user to be able to enter the number of questions they want to see for that particular testing session. Basically, you can take all the questions, or (fill in the blank) number of questions. If they choose a number, the questions would be drawn randomly from the entire question set.I would like for the user to be able to enter the number of questions they want to see for that particular testing session. Basically, you can take all the questions, or (fill in the blank) number of questions. If they choose a number, the questions would be drawn randomly from the entire question set.