[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 + 17", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "31"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Distributive property", "Commutative property", "Associative 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: 6 × 13", "difficulty": "medium", "explanation": "Multiply: 6×13=78", "needs_review": false, "correct_answer": "78"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 19", "difficulty": "medium", "explanation": "Multiply: 20×19=380", "needs_review": false, "correct_answer": "380"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 14", "difficulty": "medium", "explanation": "Multiply: 17×14=238", "needs_review": false, "correct_answer": "238"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 16", "difficulty": "medium", "explanation": "Multiply: 15×16=240", "needs_review": false, "correct_answer": "240"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 13", "difficulty": "medium", "explanation": "Multiply: 8×13=104", "needs_review": false, "correct_answer": "104"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 2", "difficulty": "medium", "explanation": "Multiply: 4×2=8", "needs_review": false, "correct_answer": "8"}]