text: # 运算符的使用
  
  a = 5
  b = 10
  c = 3
  d = 4
  e = 5
  a += b
  a -= c
  a /= e
  print("a = ", a)
  
  flag1 = 3 > 2
  flag2 = 2 < 1
  flag3 = flag1 and flag2
  flag4 = flag1 or flag2
  flag5 = not flag1
  print("flag1 = ", flag1)
  print("flag2 = ", flag2)
  print("flag3 = ", flag3)
  print("flag4 = ", flag4)
  print("flag5 = ", flag5)
  print(flag1 is True)
  print(flag2 is not True)