[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 68 + 30", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "98"}, {"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: 13 × 2", "difficulty": "medium", "explanation": "Multiply: 13×2=26", "needs_review": false, "correct_answer": "26"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 5", "difficulty": "medium", "explanation": "Multiply: 19×5=95", "needs_review": false, "correct_answer": "95"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 16", "difficulty": "medium", "explanation": "Multiply: 20×16=320", "needs_review": false, "correct_answer": "320"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 10", "difficulty": "medium", "explanation": "Multiply: 8×10=80", "needs_review": false, "correct_answer": "80"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 2 × 11", "difficulty": "medium", "explanation": "Multiply: 2×11=22", "needs_review": false, "correct_answer": "22"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 12", "difficulty": "medium", "explanation": "Multiply: 7×12=84", "needs_review": false, "correct_answer": "84"}]