[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 + 40", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "57"}, {"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: 17 × 18", "difficulty": "medium", "explanation": "Multiply: 17×18=306", "needs_review": false, "correct_answer": "306"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 20", "difficulty": "medium", "explanation": "Multiply: 17×20=340", "needs_review": false, "correct_answer": "340"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 11", "difficulty": "medium", "explanation": "Multiply: 4×11=44", "needs_review": false, "correct_answer": "44"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 13", "difficulty": "medium", "explanation": "Multiply: 13×13=169", "needs_review": false, "correct_answer": "169"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 13", "difficulty": "medium", "explanation": "Multiply: 7×13=91", "needs_review": false, "correct_answer": "91"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 20", "difficulty": "medium", "explanation": "Multiply: 12×20=240", "needs_review": false, "correct_answer": "240"}]