Untitled

import tkinter as tk

w = tk.Tk()
w.geometry("400x400")
w.title("Calculator")

result_label = tk.Label(w, text="0")
result_label.pack()

result = ""

def update_result(value):
    global result
    if value == "=":
        result_label.configure(text=str(eval(result)))
        result = ""
    else:
        if result == "0":
            result = value
        else:
            result += value
        result_label.configure(text=result)

btn_7 = tk.Button(w, text="7", command=lambda: update_result("7"))
btn_7.pack()

btn_8 = tk.Button(w, text="8", command=lambda: update_result("8"))
btn_8.pack()

btn_9 = tk.Button(w, text="9", command=lambda: update_result("9"))
btn_9.pack()

btn_4 = tk.Button(w, text="4", command=lambda: update_result("4"))
btn_4.pack()

btn_5 = tk.Button(w, text="5", command=lambda: update_result("5"))
btn_5.pack()

btn_6 = tk.Button(w, text="6", command=lambda: update_result("6"))
btn_6.pack()

btn_1 = tk.Button(w, text="1", command=lambda: update_result("1"))
btn_1.pack()

btn_2 = tk.Button(w, text="2", command=lambda: update_result("2"))
btn_2.pack()

btn_3 = tk.Button(w, text="3", command=lambda: update_result("3"))
btn_3.pack()

btn_0 = tk.Button(w, text="0", command=lambda: update_result("0"))
btn_0.pack()

btn_add = tk.Button(w, text="+", command=lambda: update_result("+"))
btn_add.pack()

btn_subtract = tk.Button(w, text="-", command=lambda: update_result("-"))
btn_subtract.pack()

btn_multiply = tk.Button(w, text="*", command=lambda: update_result("*"))
btn_multiply.pack()

btn_divide = tk.Button(w, text="/", command=lambda: update_result("/"))
btn_divide.pack()

btn_equal = tk.Button(w, text="=", command=lambda: update_result("="))
btn_equal.pack()

w.mainloop()