[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 40 + 21", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "61"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Distributive property", "Associative property", "Commutative property", "Identity 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: 17 × 7", "difficulty": "medium", "explanation": "Multiply: 17×7=119", "needs_review": false, "correct_answer": "119"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 16", "difficulty": "medium", "explanation": "Multiply: 18×16=288", "needs_review": false, "correct_answer": "288"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 19", "difficulty": "medium", "explanation": "Multiply: 5×19=95", "needs_review": false, "correct_answer": "95"}]