In our opinion, formulas question type offers to Maths and Science primary/secondary teachers everything they need to produce a high variety of Moodle quizzes. This question type was written by Hon Wai Lau. Later was upgraded to the new question engine introduced in Moodle 2.1 by Jean-Michel Védrine. At the time of this writing this version is compatible with Moodle 2.6, 2.7 and 2.8.
This question shows its full potential when used it in connection with JSXGraph. This connection was developed by Peter Haverlson
If you fancy you could try it by yourself. Click this link http://mustpro.eu/moodle/aaimg/ajsx/GraphForMoodle2.html?graph=2*x+1 and change the value of the parameters in the line equation. What you change manually it is changed randomly by the formulas question engine creating a different question for every student. Wonderful, doesn’t it?