[{"id": 1, "type": "short_answer", "skill": "area", "question": "Find the area of a rectangle: length=5, width=4", "difficulty": "medium", "explanation": "A=l×w=5×4=20 sq units.", "needs_review": false, "correct_answer": "20"}, {"id": 2, "type": "multiple_choice", "skill": "perimeter", "options": ["9", "18", "20", "20"], "question": "Find the perimeter of a rectangle: length=5, width=4", "difficulty": "medium", "explanation": "P=2(l+w)=2(5+4)=2(9)=18", "needs_review": false, "correct_answer": "18"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 10", "difficulty": "medium", "explanation": "Multiply: 13×10=130", "needs_review": false, "correct_answer": "130"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 9", "difficulty": "medium", "explanation": "Multiply: 14×9=126", "needs_review": false, "correct_answer": "126"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 14", "difficulty": "medium", "explanation": "Multiply: 13×14=182", "needs_review": false, "correct_answer": "182"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 13", "difficulty": "medium", "explanation": "Multiply: 17×13=221", "needs_review": false, "correct_answer": "221"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 18", "difficulty": "medium", "explanation": "Multiply: 14×18=252", "needs_review": false, "correct_answer": "252"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 11", "difficulty": "medium", "explanation": "Multiply: 18×11=198", "needs_review": false, "correct_answer": "198"}]