diff --git a/src/main/kotlin/PluginMain.kt b/src/main/kotlin/PluginMain.kt
index 986e51f..5ca33b3 100644
--- a/src/main/kotlin/PluginMain.kt
+++ b/src/main/kotlin/PluginMain.kt
@@ -30,13 +30,14 @@ object PluginMain : KotlinPlugin(
                     "请用以上四组数字组合成结果为24的算式，以“答”开头验证"
             }
             startsWith("答") quoteReply {
-                val game = games[this.sender.id]
+                val game = games[sender.id]
                 if (game == null) {
                     "你还没有抽数字哦，说“24点”来开始游戏吧"
                 } else {
                     try {
                         val result = game.evaluate(message.contentToString().removePrefix("答").trim())
                         if (result == 24.0) {
+                            games.remove(sender.id)
                             "恭喜你，答对了！"
                         } else {
                             "答错了，计算结果为 $result"
diff --git a/src/main/kotlin/Point24.kt b/src/main/kotlin/Point24.kt
index 5437832..8cbe262 100644
--- a/src/main/kotlin/Point24.kt
+++ b/src/main/kotlin/Point24.kt
@@ -21,8 +21,10 @@ class Point24 {
     )
 
     fun evaluate(expression: String): Double {
+        val expr = expression.replace('（', '(').replace('）', ')')
+
         val tokens = ShuntingYard.convertToRPN(
-            expression,
+            expr,
             null,
             mapOf(),
             null,
@@ -47,7 +49,7 @@ class Point24 {
         if (nums.isNotEmpty())
             throw IllegalArgumentException("必须使用所有数值")
 
-        return ExpressionBuilder(expression)
+        return ExpressionBuilder(expr)
             .implicitMultiplication(false)
             .build()
             .evaluate()