[
  {
    "type": "wordProblem",
    "grade": "grade1",
    "difficulty": "easy",
    "questionText": "小明有5顆糖果，媽媽又給他3顆，小明現在有幾顆糖果？",
    "correctAnswer": "8",
    "options": [],
    "explanation": "5+3=8",
    "subtype": "加減混合"
  },
  {
    "type": "circling",
    "grade": "grade1",
    "difficulty": "easy",
    "questionText": "請圈出 5 個蘋果",
    "correctAnswer": "5",
    "options": [],
    "explanation": "數一數有 5 個蘋果",
    "circlingData": {
      "itemEmoji": "🍎",
      "totalCount": 12,
      "targetCount": 5
    }
  },
  {
    "type": "countingMoney",
    "grade": "grade2",
    "difficulty": "medium",
    "questionText": "請圈出總共 115 元的錢幣組合",
    "correctAnswer": "115",
    "options": [],
    "explanation": "100元 + 10元 + 5元 = 115元",
    "countingMoneyData": {
      "mode": "selecting",
      "targetAmount": 115,
      "coins": [
        {"value": 100, "count": 2},
        {"value": 50, "count": 1},
        {"value": 10, "count": 3},
        {"value": 5, "count": 2}
      ]
    }
  }
]

• type: addition, subtraction, multiplication, division, wordProblem, matching, circling, countingMoney
• grade: grade1, grade2, grade3, grade4, grade5, grade6
• difficulty: easy, medium, hard
• options: 選擇題填入選項陣列，一般題目填入空陣列 []
• correctAnswer: 選擇題填選項編號（"1", "2", "3"），一般題目填答案
• explanation: 可選填，不需要可填空字串 ""
• subtype: 應用題專用，子類型名稱（選填，預設為「未分類」，會自動建立新子類型）
• circlingData: 圈選題型必須包含 {itemEmoji, totalCount, targetCount}
• countingMoneyData: 數錢幣題型必須包含 {mode, coins}，mode為"counting"或"selecting"，selecting模式需額外提供targetAmount