[{"id": 1, "type": "short_answer", "skill": "area", "question": "Find the area of a rectangle: length=5, width=3", "difficulty": "medium", "explanation": "A=l×w=5×3=15 sq units.", "needs_review": false, "correct_answer": "15"}, {"id": 2, "type": "multiple_choice", "skill": "perimeter", "options": ["16", "15", "20", "8"], "question": "Find the perimeter of a rectangle: length=5, width=3", "difficulty": "medium", "explanation": "P=2(l+w)=2(5+3)=2(8)=16", "needs_review": false, "correct_answer": "16"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 3 × 18", "difficulty": "medium", "explanation": "Multiply: 3×18=54", "needs_review": false, "correct_answer": "54"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 12", "difficulty": "medium", "explanation": "Multiply: 12×12=144", "needs_review": false, "correct_answer": "144"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 11", "difficulty": "medium", "explanation": "Multiply: 7×11=77", "needs_review": false, "correct_answer": "77"}]