[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 95 + 78", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "173"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Distributive property", "Commutative 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: 20 × 16", "difficulty": "medium", "explanation": "Multiply: 20×16=320", "needs_review": false, "correct_answer": "320"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 9", "difficulty": "medium", "explanation": "Multiply: 9×9=81", "needs_review": false, "correct_answer": "81"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 9", "difficulty": "medium", "explanation": "Multiply: 16×9=144", "needs_review": false, "correct_answer": "144"}]