A calculator, created with Tkinter and Python. See https://www.hashbangcode.com/article/creating-simple-calculator-application-tkinter-python for more informaiton.

calculator.py

import tkinter as tk

class Calculator(tk.Tk):

    def __init__(self):
        super().__init__()

        self.title("Calcuator")
        
        self.buttons = {}

        self.calculator_output = tk.Label(width=25, relief=tk.FLAT, bd=1, justify=tk.RIGHT, font="Helvetica 16")
        self.calculator_output.grid(columnspan=5, row=0)

        self.buttons['button_equals'] = tk.Button(self, text='=', font="Helvetica 16")
        self.buttons['button_equals'].config(height=6)
        self.buttons['button_equals'].config(command=lambda button='=': self.button_action(button))
        self.buttons['button_equals'].grid(column=4, row=1, rowspan=4)

        self.controls = [
            ['7','8','9','/'],
            ['4','5','6','*'],
            ['1','2','3','-'],
            ['C','0','. ','+'],
        ]

        for i in range(0, len(self.controls)):
            for j in range(0, len(self.controls[i])):
                button_label = self.controls[i][j]
                self.buttons['button_' + str(i) + '_' + str(j)] = tk.Button(self, text=button_label, font="Helvetica 16")
                self.buttons['button_' + str(i) + '_' + str(j)].config(command=lambda button=button_label: self.button_action(button))
                self.buttons['button_' + str(i) + '_' + str(j)].grid(column=j, row=i+1)

    def button_action(self, button_pressed):
        # React to the button being pressed.
        if button_pressed == '=':
            current_value = self.calculator_output.cget('text')
            try:
                result = eval(current_value)
                if result != '':
                    self.calculator_output.config(text=result)
            except:
                self.calculator_output.config(text=current_value)
        elif button_pressed == 'C':
            self.calculator_output.config(text='')
        else:
            current_value = self.calculator_output.cget('text')
            self.calculator_output.config(text=str(current_value) + button_pressed)


if __name__ == "__main__":
    calculator = Calculator()
    calculator.mainloop()