[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 25 + 15", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "40"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Associative property", "Identity property", "Commutative 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: 18 × 13", "difficulty": "medium", "explanation": "Multiply: 18×13=234", "needs_review": false, "correct_answer": "234"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 16", "difficulty": "medium", "explanation": "Multiply: 17×16=272", "needs_review": false, "correct_answer": "272"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 2", "difficulty": "medium", "explanation": "Multiply: 4×2=8", "needs_review": false, "correct_answer": "8"}]