Tkinter进入和网格

我正在尝试制作一个简单的计算器，并且希望在按钮上有一个输入小部件，但是网格无法正常工作。

这是我的代码：

from tkinter import *
w = 6
h = w - 3

root = Tk()
root.title("Calculator")

def callback():
    print("pressed")

e = Entry(root)
e.grid(row=1, column=1)

b1 = Button(root, bg='white', width=w, height=h, text="1", activebackground="black", activeforeground="white", command=callback)
b1.grid(row=2, column=1)

b2 = Button(root, bg='white', width=w, height=h, text="2", activebackground="black", activeforeground="white", command=callback)
b2.grid(row=2, column=2)

b3 = Button(root, bg='white', width=w, height=h, text="3", activebackground="black", activeforeground="white", command=callback)
b3.grid(row=2, column=3)

b4 = Button(root, bg='white', width=w, height=h, text="4", activebackground="black", activeforeground="white", command=callback)
b4.grid(row=3, column=1)

b5 = Button(root, bg='white', width=w, height=h, text="5", activebackground="black", activeforeground="white", command=callback)
b5.grid(row=3, column=2)

b6 = Button(root, bg='white', width=w, height=h, text="6", activebackground="black", activeforeground="white", command=callback)
b6.grid(row=3, column=3)

b7 = Button(root, bg='white', width=w, height=h, text="7", activebackground="black", activeforeground="white", command=callback)
b7.grid(row=4, column=1)

b8 = Button(root, bg='white', width=w, height=h, text="8", activebackground="black", activeforeground="white", command=callback)
b8.grid(row=4, column=2)

b9 = Button(root, bg='white', width=w, height=h, text="9", activebackground="black", activeforeground="white", command=callback)
b9.grid(row=4, column=3)

b0 = Button(root, bg='white', width=w, height=h, text="0", activebackground="black", activeforeground="white", command=callback)
b0.grid(row=5, column=2)

AC = Button(root, bg='white', width=w, height=h, text="AC", activebackground="black", activeforeground="white", command=callback)
AC.grid(row=5, column=1)

plus = Button(root, bg='white', width=w, height=h, text="+", activebackground="black", activeforeground="white", command=callback)
plus.grid(row=2, column=4)

minus = Button(root, bg='white', width=w, height=h, text="-", activebackground="black", activeforeground="white", command=callback)
minus.grid(row=3, column=4)

mult = Button(root, bg='white', width=w, height=h, text="×", activebackground="black", activeforeground="white", command=callback)
mult.grid(row=4, column=4)

div = Button(root, bg='white', width=w, height=h, text="÷", activebackground="black", activeforeground="white", command=callback)
div.grid(row=5, column=4)

equ = Button(root, bg='white', width=w, height=h, text="=", activebackground="black", activeforeground="white", command=callback)
equ.grid(row=5, column=3)

root.mainloop()

这是我的输出：输出

在仍然使用网格管理器的情况下，如何使程序的按钮与输入框对齐？