[{"id": 1, "type": "short_answer", "skill": "addition", "question": "Calculate: 43 + 42", "difficulty": "medium", "explanation": "Add by place value, regrouping as needed.", "needs_review": false, "correct_answer": "85"}, {"id": 2, "type": "multiple_choice", "skill": "addition", "options": ["90", "85", "95", "84"], "question": "What is the sum of 43 and 42?", "difficulty": "easy", "explanation": "43+42=85", "needs_review": false, "correct_answer": "85"}, {"id": 3, "type": "true_false", "skill": "properties", "question": "The commutative property means 43+42 = 42+43.", "difficulty": "easy", "explanation": "The commutative property states changing the order of addends does not change the sum.", "needs_review": false, "correct_answer": "True"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 7", "difficulty": "medium", "explanation": "Multiply: 20×7=140", "needs_review": false, "correct_answer": "140"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 5", "difficulty": "medium", "explanation": "Multiply: 12×5=60", "needs_review": false, "correct_answer": "60"}]