1÷0.45÷0.9-7/87/8是八分之七越快越好有简便算法更好

Question

1÷0.45÷0.9-7/8
7/8 是八分之七 越快越好 有简便算法更好

Answer 1

1÷0.45÷0.9-7/8
=1÷9/20÷9/10-7/8
=1×20/9×10/9-7/8
=200/81-7/8
=1600/648-567/648
=1033/648
=1又385/648