[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 31 + 33", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "64"}, {"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: 2 × 6", "difficulty": "medium", "explanation": "Multiply: 2×6=12", "needs_review": false, "correct_answer": "12"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 8", "difficulty": "medium", "explanation": "Multiply: 17×8=136", "needs_review": false, "correct_answer": "136"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 3 × 9", "difficulty": "medium", "explanation": "Multiply: 3×9=27", "needs_review": false, "correct_answer": "27"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 4", "difficulty": "medium", "explanation": "Multiply: 4×4=16", "needs_review": false, "correct_answer": "16"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 19", "difficulty": "medium", "explanation": "Multiply: 10×19=190", "needs_review": false, "correct_answer": "190"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 6", "difficulty": "medium", "explanation": "Multiply: 13×6=78", "needs_review": false, "correct_answer": "78"}]