def crisp(tr):
    """
    Calculates the crisp number achieved from type reduced IT2FS.
    
    Parameters
    ----------
    
    tr:
        Tuple (l, r)
        
        Type reduced IT2FS
    
    Returns
    -------
    float
    
    Returns the crisp number achieved from type reduced IT2FS.
    
    Examples
    --------
    
    >>> tr1 = (0.1, 0.3)
    >>> print(crisp(tr1))
    """
    return (tr[0] + tr[1]) / 2