[{"id": 1, "type": "short_answer", "skill": "area", "question": "Find the area of a rectangle: length=12, width=4", "difficulty": "medium", "explanation": "A=l×w=12×4=48 sq units.", "needs_review": false, "correct_answer": "48"}, {"id": 2, "type": "multiple_choice", "skill": "perimeter", "options": ["32", "16", "48", "48"], "question": "Find the perimeter of a rectangle: length=12, width=4", "difficulty": "medium", "explanation": "P=2(l+w)=2(12+4)=2(16)=32", "needs_review": false, "correct_answer": "32"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 6", "difficulty": "medium", "explanation": "Multiply: 15×6=90", "needs_review": false, "correct_answer": "90"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 5", "difficulty": "medium", "explanation": "Multiply: 13×5=65", "needs_review": false, "correct_answer": "65"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 2", "difficulty": "medium", "explanation": "Multiply: 17×2=34", "needs_review": false, "correct_answer": "34"}]