input: Write a python function to replace the variables with their values and evaluate the expression.
  assert replace_variables_and_evaluate("10 + 25") == 35
  assert replace_variables_and_evaluate("5 * 3 + 2") == 17
  assert replace_variables_and_evaluate("100 / 4 - 10") == 15
output: def replace_variables_and_evaluate(expression: str) -> int:
      return eval(expression)