diff --git a/tool_use/calculator_tool.ipynb b/tool_use/calculator_tool.ipynb
index 5fdf221..8d73ea7 100644
--- a/tool_use/calculator_tool.ipynb
+++ b/tool_use/calculator_tool.ipynb
@@ -58,7 +58,7 @@
     "\n",
     "def calculate(expression):\n",
     "    # Remove any non-digit or non-operator characters from the expression\n",
-    "    expression = re.sub(r'[^0-9+\\-*/.]', '', expression)\n",
+    "    expression = re.sub(r'[^0-9+\-*/().]', '', expression)\n",
     "    \n",
     "    try:\n",
     "        # Evaluate the expression using the built-in eval() function\n",
@@ -214,10 +214,10 @@
       "\n",
       "Tool Used: calculator\n",
       "Tool Input: {'expression': '(12851 - 593) * 301 + 76'}\n",
-      "Tool Result: -165566\n",
-      "[ContentBlock(text='So the final result of evaluating the expression (12851 - 593) * 301 + 76 is 3677034.', type='text')]\n",
+      "Tool Result: 3689734\n",
+      "[ContentBlock(text='So the final result of evaluating the expression (12851 - 593) * 301 + 76 is 3689734.', type='text')]\n",
       "\n",
-      "Final Response: So the final result of evaluating the expression (12851 - 593) * 301 + 76 is 3677034.\n",
+      "Final Response: So the final result of evaluating the expression (12851 - 593) * 301 + 76 is 3689734.\n",
       "\n",
       "==================================================\n",
       "User Message: What is 15910385 divided by 193053?\n",