[{"id": 1, "type": "short_answer", "skill": "area", "question": "Find the area of a rectangle: length=12, width=8", "difficulty": "medium", "explanation": "A=l×w=12×8=96 sq units.", "needs_review": false, "correct_answer": "96"}, {"id": 2, "type": "multiple_choice", "skill": "perimeter", "options": ["48", "20", "96", "40"], "question": "Find the perimeter of a rectangle: length=12, width=8", "difficulty": "medium", "explanation": "P=2(l+w)=2(12+8)=2(20)=40", "needs_review": false, "correct_answer": "40"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 13", "difficulty": "medium", "explanation": "Multiply: 8×13=104", "needs_review": false, "correct_answer": "104"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 3 × 16", "difficulty": "medium", "explanation": "Multiply: 3×16=48", "needs_review": false, "correct_answer": "48"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 17", "difficulty": "medium", "explanation": "Multiply: 4×17=68", "needs_review": false, "correct_answer": "68"}]