def numerical_equal(a: str, b: str) -> Union[bool, None]:
    """
    Check if two strings are numerical equal.
    """
    a_int = convert_to_int(a)
    b_int = convert_to_int(b)

    if a_int is not None and b_int is not None:
        return a_int == b_int

    a_float = convert_to_float(a)
    b_float = convert_to_float(b)

    if a_float is not None and b_float is not None:
        return isclose(a_float, b_float, rel_tol=1e-3)

    return None

    Check if two strings are numerical equal.
    
envs/rstar/eval_src/toolkit_for_MATH/latex_answer_check.py