[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 68 + 55", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "123"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Identity property", "Distributive property", "Associative property", "Commutative 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 × 7", "difficulty": "medium", "explanation": "Multiply: 4×7=28", "needs_review": false, "correct_answer": "28"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 2 × 18", "difficulty": "medium", "explanation": "Multiply: 2×18=36", "needs_review": false, "correct_answer": "36"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 9", "difficulty": "medium", "explanation": "Multiply: 15×9=135", "needs_review": false, "correct_answer": "135"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 18", "difficulty": "medium", "explanation": "Multiply: 7×18=126", "needs_review": false, "correct_answer": "126"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 11", "difficulty": "medium", "explanation": "Multiply: 11×11=121", "needs_review": false, "correct_answer": "121"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 16", "difficulty": "medium", "explanation": "Multiply: 12×16=192", "needs_review": false, "correct_answer": "192"}]