[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 61 + 76", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "137"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Identity property", "Associative property", "Commutative 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: 7 × 13", "difficulty": "medium", "explanation": "Multiply: 7×13=91", "needs_review": false, "correct_answer": "91"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 4", "difficulty": "medium", "explanation": "Multiply: 12×4=48", "needs_review": false, "correct_answer": "48"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 7", "difficulty": "medium", "explanation": "Multiply: 4×7=28", "needs_review": false, "correct_answer": "28"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 2", "difficulty": "medium", "explanation": "Multiply: 20×2=40", "needs_review": false, "correct_answer": "40"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 2", "difficulty": "medium", "explanation": "Multiply: 12×2=24", "needs_review": false, "correct_answer": "24"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 20 × 19", "difficulty": "medium", "explanation": "Multiply: 20×19=380", "needs_review": false, "correct_answer": "380"}]