[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 47 + 71", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "118"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Distributive property", "Associative property", "Commutative 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: 3 × 13", "difficulty": "medium", "explanation": "Multiply: 3×13=39", "needs_review": false, "correct_answer": "39"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 5", "difficulty": "medium", "explanation": "Multiply: 6×5=30", "needs_review": false, "correct_answer": "30"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 2 × 6", "difficulty": "medium", "explanation": "Multiply: 2×6=12", "needs_review": false, "correct_answer": "12"}, {"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: 18 × 11", "difficulty": "medium", "explanation": "Multiply: 18×11=198", "needs_review": false, "correct_answer": "198"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 20", "difficulty": "medium", "explanation": "Multiply: 13×20=260", "needs_review": false, "correct_answer": "260"}]