[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 83 + 78", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "161"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Commutative property", "Distributive property", "Identity property", "Associative 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 × 4", "difficulty": "medium", "explanation": "Multiply: 19×4=76", "needs_review": false, "correct_answer": "76"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 18", "difficulty": "medium", "explanation": "Multiply: 17×18=306", "needs_review": false, "correct_answer": "306"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 8", "difficulty": "medium", "explanation": "Multiply: 9×8=72", "needs_review": false, "correct_answer": "72"}]