diff --git a/aula202-calculadora/buttons.py b/aula202-calculadora/buttons.py
index 1e34af7..e5e154a 100644
--- a/aula202-calculadora/buttons.py
+++ b/aula202-calculadora/buttons.py
@@ -3,7 +3,7 @@ from typing import TYPE_CHECKING
 
 from PySide6.QtCore import Slot
 from PySide6.QtWidgets import QGridLayout, QPushButton
-from utils import isEmpty, isNumOrDot, isValidNumber
+from utils import converToNumber, isEmpty, isNumOrDot, isValidNumber
 from variables import MEDIUM_FONT_SIZE
 
 if TYPE_CHECKING:
@@ -36,7 +36,7 @@ class ButtonsGrid(QGridLayout):
             ['7', '8', '9', '*'],
             ['4', '5', '6', '-'],
             ['1', '2', '3', '+'],
-            ['',  '0', '.', '='],
+            ['N',  '0', '.', '='],
         ]
         self.display = display
         self.info = info
@@ -90,6 +90,9 @@ class ButtonsGrid(QGridLayout):
         if text == 'D':
             self._connectButtonClicked(button, self.display.backspace)
 
+        if text == 'N':
+            self._connectButtonClicked(button, self._invertNumber)
+
         if text in '+-/*^':
             self._connectButtonClicked(
                 button,
@@ -106,6 +109,16 @@ class ButtonsGrid(QGridLayout):
             func(*args, **kwargs)
         return realSlot
 
+    @Slot()
+    def _invertNumber(self):
+        displayText = self.display.text()
+
+        if not isValidNumber(displayText):
+            return
+
+        number = converToNumber(displayText) * -1
+        self.display.setText(str(number))
+
     @Slot()
     def _insertToDisplay(self, text):
         newDisplayValue = self.display.text() + text
@@ -137,7 +150,7 @@ class ButtonsGrid(QGridLayout):
         # Se houver algo no número da esquerda,
         # não fazemos nada. Aguardaremos o número da direita.
         if self._left is None:
-            self._left = float(displayText)
+            self._left = converToNumber(displayText)
 
         self._op = text
         self.equation = f'{self._left} {self._op} ??'
@@ -150,7 +163,7 @@ class ButtonsGrid(QGridLayout):
             self._showError('Conta incompleta.')
             return
 
-        self._right = float(displayText)
+        self._right = converToNumber(displayText)
         self.equation = f'{self._left} {self._op} {self._right}'
         result = 'error'
 
diff --git a/aula202-calculadora/utils.py b/aula202-calculadora/utils.py
index e28ca00..adf9f91 100644
--- a/aula202-calculadora/utils.py
+++ b/aula202-calculadora/utils.py
@@ -7,6 +7,15 @@ def isNumOrDot(string: str):
     return bool(NUM_OR_DOT_REGEX.search(string))
 
 
+def converToNumber(string: str):
+    number = float(string)
+
+    if number.is_integer():
+        number = int(number)
+
+    return number
+
+
 def isValidNumber(string: str):
     valid = False
     try: