In course specification for the course I teach there should be two mid-term exams. For each one that total marks should be 20. I forgot about that and gave the students the first mid-term with only 15 multiple choice (1 mark for each).
Now how can I correct my mistake? Should I give them a bonus of 5 marks or what is the best way to correct my mistake?
It also would be helpful to suggest a book that discuss such situations.