[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 + 31", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "45"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Identity property", "Associative property", "Commutative 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: 6 × 13", "difficulty": "medium", "explanation": "Multiply: 6×13=78", "needs_review": false, "correct_answer": "78"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 11", "difficulty": "medium", "explanation": "Multiply: 11×11=121", "needs_review": false, "correct_answer": "121"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 3 × 11", "difficulty": "medium", "explanation": "Multiply: 3×11=33", "needs_review": false, "correct_answer": "33"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 19", "difficulty": "medium", "explanation": "Multiply: 6×19=114", "needs_review": false, "correct_answer": "114"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 15", "difficulty": "medium", "explanation": "Multiply: 20×15=300", "needs_review": false, "correct_answer": "300"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 8 × 9", "difficulty": "medium", "explanation": "Multiply: 8×9=72", "needs_review": false, "correct_answer": "72"}]