[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 27 + 38", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "65"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Identity property", "Associative property", "Distributive property", "Commutative 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: 7 × 3", "difficulty": "medium", "explanation": "Multiply: 7×3=21", "needs_review": false, "correct_answer": "21"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 20", "difficulty": "medium", "explanation": "Multiply: 4×20=80", "needs_review": false, "correct_answer": "80"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 6", "difficulty": "medium", "explanation": "Multiply: 19×6=114", "needs_review": false, "correct_answer": "114"}]