[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 98 + 91", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "189"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Identity property", "Commutative property", "Distributive 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: 10 × 10", "difficulty": "medium", "explanation": "Multiply: 10×10=100", "needs_review": false, "correct_answer": "100"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 4", "difficulty": "medium", "explanation": "Multiply: 20×4=80", "needs_review": false, "correct_answer": "80"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 2", "difficulty": "medium", "explanation": "Multiply: 20×2=40", "needs_review": false, "correct_answer": "40"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 11", "difficulty": "medium", "explanation": "Multiply: 19×11=209", "needs_review": false, "correct_answer": "209"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 9", "difficulty": "medium", "explanation": "Multiply: 9×9=81", "needs_review": false, "correct_answer": "81"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 5", "difficulty": "medium", "explanation": "Multiply: 19×5=95", "needs_review": false, "correct_answer": "95"}]