[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 64 + 21", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "85"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Distributive property", "Associative property", "Identity 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: 6 × 11", "difficulty": "medium", "explanation": "Multiply: 6×11=66", "needs_review": false, "correct_answer": "66"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 14", "difficulty": "medium", "explanation": "Multiply: 11×14=154", "needs_review": false, "correct_answer": "154"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 16 × 13", "difficulty": "medium", "explanation": "Multiply: 16×13=208", "needs_review": false, "correct_answer": "208"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 11", "difficulty": "medium", "explanation": "Multiply: 4×11=44", "needs_review": false, "correct_answer": "44"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 20", "difficulty": "medium", "explanation": "Multiply: 19×20=380", "needs_review": false, "correct_answer": "380"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 3", "difficulty": "medium", "explanation": "Multiply: 14×3=42", "needs_review": false, "correct_answer": "42"}]