def calculate(num1, operator, num2):
  """
  Performs the specified arithmetic operation on two numbers.

  Args:
    num1: The first number.
    operator: The arithmetic operator (+, -, *, /).
    num2: The second number.

  Returns:
    The result of the operation, or None if an error occurs.
  """

  if operator == "+":
    return num1 + num2
  elif operator == "-":
    return num1 - num2
  elif operator == "*":
    return num1 * num2
  elif operator == "/":
    if num2 == 0:
      print("Error: Division by zero")
      return None
    else:
      return num1 / num2
  else:
    print("Error: Invalid operator")
    return None

# Example usage
num1 = 10
num2 = 5
operator = "+"

result = calculate(num1, operator, num2)

if result is not None:
  print(f"{num1} {operator} {num2} = {result}")