[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 + 86", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "97"}, {"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 × 12", "difficulty": "medium", "explanation": "Multiply: 19×12=228", "needs_review": false, "correct_answer": "228"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 17", "difficulty": "medium", "explanation": "Multiply: 15×17=255", "needs_review": false, "correct_answer": "255"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 10 × 10", "difficulty": "medium", "explanation": "Multiply: 10×10=100", "needs_review": false, "correct_answer": "100"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 15 × 16", "difficulty": "medium", "explanation": "Multiply: 15×16=240", "needs_review": false, "correct_answer": "240"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 3", "difficulty": "medium", "explanation": "Multiply: 13×3=39", "needs_review": false, "correct_answer": "39"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 20", "difficulty": "medium", "explanation": "Multiply: 9×20=180", "needs_review": false, "correct_answer": "180"}]