[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 99 + 37", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "136"}, {"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: 2 × 9", "difficulty": "medium", "explanation": "Multiply: 2×9=18", "needs_review": false, "correct_answer": "18"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 14 × 12", "difficulty": "medium", "explanation": "Multiply: 14×12=168", "needs_review": false, "correct_answer": "168"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 17 × 6", "difficulty": "medium", "explanation": "Multiply: 17×6=102", "needs_review": false, "correct_answer": "102"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 11", "difficulty": "medium", "explanation": "Multiply: 7×11=77", "needs_review": false, "correct_answer": "77"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 4 × 18", "difficulty": "medium", "explanation": "Multiply: 4×18=72", "needs_review": false, "correct_answer": "72"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 13 × 2", "difficulty": "medium", "explanation": "Multiply: 13×2=26", "needs_review": false, "correct_answer": "26"}]