[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 65 + 12", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "77"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Commutative property", "Identity 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: 4 × 4", "difficulty": "medium", "explanation": "Multiply: 4×4=16", "needs_review": false, "correct_answer": "16"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 15", "difficulty": "medium", "explanation": "Multiply: 15×15=225", "needs_review": false, "correct_answer": "225"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 9", "difficulty": "medium", "explanation": "Multiply: 20×9=180", "needs_review": false, "correct_answer": "180"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 13", "difficulty": "medium", "explanation": "Multiply: 11×13=143", "needs_review": false, "correct_answer": "143"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 17", "difficulty": "medium", "explanation": "Multiply: 13×17=221", "needs_review": false, "correct_answer": "221"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 8", "difficulty": "medium", "explanation": "Multiply: 18×8=144", "needs_review": false, "correct_answer": "144"}]