[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 + 52", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "65"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Associative property", "Identity property", "Commutative property", "Distributive 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: 11 × 19", "difficulty": "medium", "explanation": "Multiply: 11×19=209", "needs_review": false, "correct_answer": "209"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 13", "difficulty": "medium", "explanation": "Multiply: 4×13=52", "needs_review": false, "correct_answer": "52"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 13", "difficulty": "medium", "explanation": "Multiply: 9×13=117", "needs_review": false, "correct_answer": "117"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 10", "difficulty": "medium", "explanation": "Multiply: 5×10=50", "needs_review": false, "correct_answer": "50"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 17", "difficulty": "medium", "explanation": "Multiply: 14×17=238", "needs_review": false, "correct_answer": "238"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 13", "difficulty": "medium", "explanation": "Multiply: 20×13=260", "needs_review": false, "correct_answer": "260"}]