[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 48 + 21", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "69"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Associative property", "Distributive 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: 8 × 9", "difficulty": "medium", "explanation": "Multiply: 8×9=72", "needs_review": false, "correct_answer": "72"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 5", "difficulty": "medium", "explanation": "Multiply: 17×5=85", "needs_review": false, "correct_answer": "85"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 2 × 17", "difficulty": "medium", "explanation": "Multiply: 2×17=34", "needs_review": false, "correct_answer": "34"}]