[{"id": 1, "type": "short_answer", "skill": "area", "question": "Find the area of a rectangle: length=8, width=6", "difficulty": "medium", "explanation": "A=l×w=8×6=48 sq units.", "needs_review": false, "correct_answer": "48"}, {"id": 2, "type": "multiple_choice", "skill": "perimeter", "options": ["48", "14", "28", "32"], "question": "Find the perimeter of a rectangle: length=8, width=6", "difficulty": "medium", "explanation": "P=2(l+w)=2(8+6)=2(14)=28", "needs_review": false, "correct_answer": "28"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 6", "difficulty": "medium", "explanation": "Multiply: 20×6=120", "needs_review": false, "correct_answer": "120"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 12", "difficulty": "medium", "explanation": "Multiply: 9×12=108", "needs_review": false, "correct_answer": "108"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 4", "difficulty": "medium", "explanation": "Multiply: 8×4=32", "needs_review": false, "correct_answer": "32"}]