text: x = 4
  y = 5
  z = 6
  
  print("x + y:")
  print(x + y)
  print(" ")
  print("z * 3:")
  print(z * 3)
  print(" ")
  print("x - z:")
  print(x - z)
  print(" ")
  print("z / x:")
  print(z / x)
  print(" ")
  print("y ** x:")
  print(y ** x)
  print(" ")
  print("z % y:")
  print(z % y)
  print(" ")
  print("-x:")
  print(-x)