[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 71 + 80", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "151"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Distributive property", "Identity property", "Commutative property", "Associative 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 × 14", "difficulty": "medium", "explanation": "Multiply: 4×14=56", "needs_review": false, "correct_answer": "56"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 3 × 20", "difficulty": "medium", "explanation": "Multiply: 3×20=60", "needs_review": false, "correct_answer": "60"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 7", "difficulty": "medium", "explanation": "Multiply: 14×7=98", "needs_review": false, "correct_answer": "98"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 9", "difficulty": "medium", "explanation": "Multiply: 6×9=54", "needs_review": false, "correct_answer": "54"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 4", "difficulty": "medium", "explanation": "Multiply: 14×4=56", "needs_review": false, "correct_answer": "56"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 2 × 16", "difficulty": "medium", "explanation": "Multiply: 2×16=32", "needs_review": false, "correct_answer": "32"}, {"id": 9, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 17", "difficulty": "medium", "explanation": "Multiply: 7×17=119", "needs_review": false, "correct_answer": "119"}, {"id": 10, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 12", "difficulty": "medium", "explanation": "Multiply: 9×12=108", "needs_review": false, "correct_answer": "108"}, {"id": 11, "type": "short_answer", "skill": "computation", "question": "Calculate: 5 × 5", "difficulty": "medium", "explanation": "Multiply: 5×5=25", "needs_review": false, "correct_answer": "25"}, {"id": 12, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 7", "difficulty": "medium", "explanation": "Multiply: 4×7=28", "needs_review": false, "correct_answer": "28"}]