[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 93 + 60", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "153"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Distributive property", "Associative 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: 20 × 15", "difficulty": "medium", "explanation": "Multiply: 20×15=300", "needs_review": false, "correct_answer": "300"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 6", "difficulty": "medium", "explanation": "Multiply: 6×6=36", "needs_review": false, "correct_answer": "36"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 3", "difficulty": "medium", "explanation": "Multiply: 6×3=18", "needs_review": false, "correct_answer": "18"}]