[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 42 + 35", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "77"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Commutative property", "Associative property", "Identity 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 × 9", "difficulty": "medium", "explanation": "Multiply: 6×9=54", "needs_review": false, "correct_answer": "54"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 11", "difficulty": "medium", "explanation": "Multiply: 20×11=220", "needs_review": false, "correct_answer": "220"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 10", "difficulty": "medium", "explanation": "Multiply: 19×10=190", "needs_review": false, "correct_answer": "190"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 15", "difficulty": "medium", "explanation": "Multiply: 18×15=270", "needs_review": false, "correct_answer": "270"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 18", "difficulty": "medium", "explanation": "Multiply: 11×18=198", "needs_review": false, "correct_answer": "198"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 14", "difficulty": "medium", "explanation": "Multiply: 19×14=266", "needs_review": false, "correct_answer": "266"}]