[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 52 + 87", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "139"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Associative property", "Identity property", "Distributive 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: 17 × 5", "difficulty": "medium", "explanation": "Multiply: 17×5=85", "needs_review": false, "correct_answer": "85"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 17", "difficulty": "medium", "explanation": "Multiply: 12×17=204", "needs_review": false, "correct_answer": "204"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 20", "difficulty": "medium", "explanation": "Multiply: 12×20=240", "needs_review": false, "correct_answer": "240"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 3 × 8", "difficulty": "medium", "explanation": "Multiply: 3×8=24", "needs_review": false, "correct_answer": "24"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 11", "difficulty": "medium", "explanation": "Multiply: 15×11=165", "needs_review": false, "correct_answer": "165"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 3 × 19", "difficulty": "medium", "explanation": "Multiply: 3×19=57", "needs_review": false, "correct_answer": "57"}]