[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 87 + 42", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "129"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Distributive property", "Associative property", "Commutative 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: 19 × 6", "difficulty": "medium", "explanation": "Multiply: 19×6=114", "needs_review": false, "correct_answer": "114"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 6", "difficulty": "medium", "explanation": "Multiply: 10×6=60", "needs_review": false, "correct_answer": "60"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 7", "difficulty": "medium", "explanation": "Multiply: 11×7=77", "needs_review": false, "correct_answer": "77"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 12", "difficulty": "medium", "explanation": "Multiply: 19×12=228", "needs_review": false, "correct_answer": "228"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 14", "difficulty": "medium", "explanation": "Multiply: 16×14=224", "needs_review": false, "correct_answer": "224"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 6", "difficulty": "medium", "explanation": "Multiply: 12×6=72", "needs_review": false, "correct_answer": "72"}]