[{"id": 1, "type": "short_answer", "skill": "area", "question": "Find the area of a rectangle: length=10, width=5", "difficulty": "medium", "explanation": "A=l×w=10×5=50 sq units.", "needs_review": false, "correct_answer": "50"}, {"id": 2, "type": "multiple_choice", "skill": "perimeter", "options": ["15", "40", "50", "30"], "question": "Find the perimeter of a rectangle: length=10, width=5", "difficulty": "medium", "explanation": "P=2(l+w)=2(10+5)=2(15)=30", "needs_review": false, "correct_answer": "30"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 17", "difficulty": "medium", "explanation": "Multiply: 17×17=289", "needs_review": false, "correct_answer": "289"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 19", "difficulty": "medium", "explanation": "Multiply: 13×19=247", "needs_review": false, "correct_answer": "247"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 18", "difficulty": "medium", "explanation": "Multiply: 4×18=72", "needs_review": false, "correct_answer": "72"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 2", "difficulty": "medium", "explanation": "Multiply: 14×2=28", "needs_review": false, "correct_answer": "28"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 5", "difficulty": "medium", "explanation": "Multiply: 12×5=60", "needs_review": false, "correct_answer": "60"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 12", "difficulty": "medium", "explanation": "Multiply: 6×12=72", "needs_review": false, "correct_answer": "72"}]