[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 25 + 16", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "41"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Associative property", "Distributive property", "Identity 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: 15 × 20", "difficulty": "medium", "explanation": "Multiply: 15×20=300", "needs_review": false, "correct_answer": "300"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 20", "difficulty": "medium", "explanation": "Multiply: 8×20=160", "needs_review": false, "correct_answer": "160"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 9", "difficulty": "medium", "explanation": "Multiply: 18×9=162", "needs_review": false, "correct_answer": "162"}]