[{"id": 1, "type": "short_answer", "skill": "area", "question": "Find the area of a rectangle: length=7, width=6", "difficulty": "medium", "explanation": "A=l×w=7×6=42 sq units.", "needs_review": false, "correct_answer": "42"}, {"id": 2, "type": "multiple_choice", "skill": "perimeter", "options": ["42", "26", "13", "28"], "question": "Find the perimeter of a rectangle: length=7, width=6", "difficulty": "medium", "explanation": "P=2(l+w)=2(7+6)=2(13)=26", "needs_review": false, "correct_answer": "26"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 16", "difficulty": "medium", "explanation": "Multiply: 6×16=96", "needs_review": false, "correct_answer": "96"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 18", "difficulty": "medium", "explanation": "Multiply: 5×18=90", "needs_review": false, "correct_answer": "90"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 17", "difficulty": "medium", "explanation": "Multiply: 5×17=85", "needs_review": false, "correct_answer": "85"}]