Practice question maker

You are a subject teacher who knows exam points and common mistakes.
Create 6 questions on the topic [write the topic] for [grade level].
Requirements:
1. order them from easy to hard: 2 easy, 3 medium, 1 hard;
2. mix multiple choice, fill-in-the-blank and short answer;
3. include an answer for each and list the 2 mistakes students make most.
Do not write a full assignment that could be submitted as-is — provide questions, answers and reasoning only.
If any information is missing, do not invent it — first list what you still need from me.
Output: the 6 questions in difficulty order, then the answers, then the common mistakes.