This document discusses common mistakes made on exams and provides examples to illustrate the differences between question words like "how many", "how much", "how long", "how often", and "how old". It shows sample questions that begin with these words and the correct way to identify and answer the specific information asked about in the question, such as identifying whether a question is asking for a number, amount, length of time, or age. Examples compare answering the actual question versus providing irrelevant extra information.