Массив 7x7 на tkinter

from tkinter import *
from tkinter import ttk
root = Tk()
root.title("Метод Place")
root.resizable(0,0)
root_width=400
root_height=400
win_width=root.winfo_screenwidth()
win_height=root.winfo_screenheight()
x=int(win_width/2-root_width/2)
y=int(win_height/2-root_height/2)
root_params=f'{root_width}x{root_height}+{x}+{y}'
root.geometry(root_params)
btn1 = ttk.Button(text='Max', width=5)
btn1.place(x=,y=) #координаты не заданы ещё
btn2 = ttk.Button(text='Max', width=5)
btn2.place(x=,y=) #координаты не заданы ещё
btn3 = ttk.Button(text='Сумма', width=6)
btn3.place(x=,y=) #координаты не заданы ещё
btn4 = ttk.Button(text='Среднее Арифметическое', width=12)
btn4.place(x=,y=) #координаты не заданы ещё
root.mainloop() #запуск окна

from random import randint
from tkinter import Tk, Frame, Button, Label
MIN_VALUE = 0
MAX_VALUE = 10
 
def update():
  sumLabel.configure(text="")
  avgLabel.configure(text="")
  frame.matrix.clear()
  for row in range(7):
    line = []
    for column in range(7):
      line.append(randint(MIN_VALUE,MAX_VALUE))
    frame.matrix.append(line)
  for label in frame.winfo_children():
    label.destroy()
  for row in range(7):
    for column in range(7):
      label = Label(frame, text=str(frame.matrix[row][column]), borderwidth=1, relief="solid")
      label.grid(row=row, column=column, sticky="EW")
 
def findMin():
  minValue = MAX_VALUE
  for row in frame.matrix:
    minValue = min(minValue, min(row))
  for row in range(7):
    for column in range(7):
      if frame.matrix[row][column]==minValue:
        label = frame.grid_slaves(row=row, column=column)[0]
        label.configure(bg="red")
 
def findMax():
  maxValue = MIN_VALUE
  for row in frame.matrix:
    maxValue = max(maxValue, max(row))
  for row in range(7):
    for column in range(7):
      if frame.matrix[row][column]==maxValue:
        label = frame.grid_slaves(row=row, column=column)[0]
        label.configure(bg="green")
 
def findSum():
  result = 0
  for row in frame.matrix:
    result = result + sum(row)
  sumLabel.configure(text=str(result))
 
def findAvg():
  numbers = []
  for row in range(7):
    for column in range(7):
      numbers.append(frame.matrix[row][column])
  result = round(sum(numbers)/len(numbers),4)
  avgLabel.configure(text=str(result))
 
root = Tk()
frame = Frame(root)
frame.matrix = []
frame.grid(row=0, column=0, columnspan=2)
Button(root, text="Новая таблица", command=update).grid(row=1, column=0, columnspan=2)
Button(root, text="Min", command=findMin, bg="red").grid(row=2, column=0)
Button(root, text="Max", command=findMax, bg="green").grid(row=2, column=1)
Button(root, text="Сумма", command=findSum).grid(row=3, column=0)
sumLabel = Label(root)
sumLabel.grid(row=3, column=1)
Button(root, text="Среднее", command=findAvg).grid(row=4, column=0)
avgLabel = Label(root)
avgLabel.grid(row=4, column=1)
update()
root.mainloop()

  for label in frame.winfo_children():
    label.destroy()