[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 79 + 71", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "150"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Commutative property", "Identity property", "Associative 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: 16 × 8", "difficulty": "medium", "explanation": "Multiply: 16×8=128", "needs_review": false, "correct_answer": "128"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 6", "difficulty": "medium", "explanation": "Multiply: 14×6=84", "needs_review": false, "correct_answer": "84"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 20", "difficulty": "medium", "explanation": "Multiply: 4×20=80", "needs_review": false, "correct_answer": "80"}]