56°2′÷6+35°39′40〃
=【（54+2）°+2*60〃】÷6+35°39′40〃
=54°÷6+2*60′÷6+2*60〃÷6+35°39′40〃
=9°20′20〃+35°39′40〃
=44°59′60〃
=45°