[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 75 + 29", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "104"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Distributive property", "Identity property", "Associative 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: 16 × 9", "difficulty": "medium", "explanation": "Multiply: 16×9=144", "needs_review": false, "correct_answer": "144"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 6 × 17", "difficulty": "medium", "explanation": "Multiply: 6×17=102", "needs_review": false, "correct_answer": "102"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 12 × 15", "difficulty": "medium", "explanation": "Multiply: 12×15=180", "needs_review": false, "correct_answer": "180"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 7", "difficulty": "medium", "explanation": "Multiply: 9×7=63", "needs_review": false, "correct_answer": "63"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 18 × 19", "difficulty": "medium", "explanation": "Multiply: 18×19=342", "needs_review": false, "correct_answer": "342"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 9 × 19", "difficulty": "medium", "explanation": "Multiply: 9×19=171", "needs_review": false, "correct_answer": "171"}]