[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 + 57", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "71"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Commutative property", "Identity property", "Associative property", "Distributive property"], "question": "Which property states a+0=a?", "difficulty": "easy", "explanation": "The identity property of addition states that adding 0 to any number gives that number.", "needs_review": false, "correct_answer": "Identity property"}, {"id": 3, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 12", "difficulty": "medium", "explanation": "Multiply: 19×12=228", "needs_review": false, "correct_answer": "228"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 7", "difficulty": "medium", "explanation": "Multiply: 5×7=35", "needs_review": false, "correct_answer": "35"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 8", "difficulty": "medium", "explanation": "Multiply: 13×8=104", "needs_review": false, "correct_answer": "104"}]