[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 87 + 18", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "105"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Commutative property", "Identity property", "Associative 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: 4 × 4", "difficulty": "medium", "explanation": "Multiply: 4×4=16", "needs_review": false, "correct_answer": "16"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 14", "difficulty": "medium", "explanation": "Multiply: 19×14=266", "needs_review": false, "correct_answer": "266"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 7", "difficulty": "medium", "explanation": "Multiply: 18×7=126", "needs_review": false, "correct_answer": "126"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 14", "difficulty": "medium", "explanation": "Multiply: 12×14=168", "needs_review": false, "correct_answer": "168"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 2", "difficulty": "medium", "explanation": "Multiply: 10×2=20", "needs_review": false, "correct_answer": "20"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 14", "difficulty": "medium", "explanation": "Multiply: 12×14=168", "needs_review": false, "correct_answer": "168"}]