1) (3-112.5%+7分之8)×13分之21÷56分之179
=(3-9/8+8/7)*21/13*56/179
=169/56*21/13*56/179
=273/179
2)[3分之7+(5.4-3分之11)×3分之5]÷9分之31
=[7/3+9-55/9]*9/31
=21/31+81/31-55/31
=(21+81-55)/31
=47/31
(3-112.5%+8/7)×21/13÷179/56
=169/56×21/13×56/179
=169/179×21/13
=273/179
【7/3+(5.4-11/3)×5/3】÷31/9
=【7/3+9-55/9】×9/31
=7/3×9/31+9×9/31-55/9×9/31
=27/31+81/31-55/31
=47/31