[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 24 + 71", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "95"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Commutative property", "Distributive 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: 2 × 13", "difficulty": "medium", "explanation": "Multiply: 2×13=26", "needs_review": false, "correct_answer": "26"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 15", "difficulty": "medium", "explanation": "Multiply: 19×15=285", "needs_review": false, "correct_answer": "285"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 2", "difficulty": "medium", "explanation": "Multiply: 7×2=14", "needs_review": false, "correct_answer": "14"}]