[{"id": 1, "type": "short_answer", "skill": "computation", "question": "Calculate: 80 + 93", "difficulty": "medium", "explanation": "Add systematically.", "needs_review": false, "correct_answer": "173"}, {"id": 2, "type": "multiple_choice", "skill": "properties", "options": ["Associative property", "Distributive 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: 9 × 19", "difficulty": "medium", "explanation": "Multiply: 9×19=171", "needs_review": false, "correct_answer": "171"}, {"id": 4, "type": "short_answer", "skill": "computation", "question": "Calculate: 7 × 20", "difficulty": "medium", "explanation": "Multiply: 7×20=140", "needs_review": false, "correct_answer": "140"}, {"id": 5, "type": "short_answer", "skill": "computation", "question": "Calculate: 11 × 17", "difficulty": "medium", "explanation": "Multiply: 11×17=187", "needs_review": false, "correct_answer": "187"}, {"id": 6, "type": "short_answer", "skill": "computation", "question": "Calculate: 2 × 6", "difficulty": "medium", "explanation": "Multiply: 2×6=12", "needs_review": false, "correct_answer": "12"}, {"id": 7, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 2", "difficulty": "medium", "explanation": "Multiply: 19×2=38", "needs_review": false, "correct_answer": "38"}, {"id": 8, "type": "short_answer", "skill": "computation", "question": "Calculate: 19 × 8", "difficulty": "medium", "explanation": "Multiply: 19×8=152", "needs_review": false, "correct_answer": "152"}]