[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 57 + 68", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "125"}, {"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: 15 × 5", "difficulty": "medium", "explanation": "Multiply: 15×5=75", "needs_review": false, "correct_answer": "75"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 2", "difficulty": "medium", "explanation": "Multiply: 9×2=18", "needs_review": false, "correct_answer": "18"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 14", "difficulty": "medium", "explanation": "Multiply: 10×14=140", "needs_review": false, "correct_answer": "140"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 3", "difficulty": "medium", "explanation": "Multiply: 6×3=18", "needs_review": false, "correct_answer": "18"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 2", "difficulty": "medium", "explanation": "Multiply: 19×2=38", "needs_review": false, "correct_answer": "38"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 7", "difficulty": "medium", "explanation": "Multiply: 8×7=56", "needs_review": false, "correct_answer": "56"}]