5÷0.5/0.6÷0.6/0.7÷0.7/0.8÷0.8/0.9
=5×0.6/0.5×0.7/0.6×0.8/0.7×0.9/0.8
=5×1/0.5×0.9
=10×0.9
=9
5除以（0.5/0.6）除以(0.6/0.7除以（O.7/0.8）除以（0.8、0.9） 简便计算
5÷0.5/0.6÷0.6/0.7÷0.7/0.8÷0.8/0.9
=5×0.6/0.5×0.7/0.6×0.8/0.7×0.9/0.8
=5×1/0.5×0.9
=10×0.9
=9