12分之5与5分之2的积除1与4分之一的差,商是多少

第一题
(5/12 x 2/5) / (1 - 1/4)
=(1/6) / (3/4)
=(1/6) x (4/3)
=2/9
第二题:
[80.4 x (1/3) - 5.3] / (1/3)
=[26.8 - 5.3] / (1/3)
=23.5 / (1/3)
=23.5 x 3
=70.5