（8/9+1/6）×72%【递等式】
问题描述：
（8/9+1/6）×72%【递等式】
答
=8/9×0.72+1/6×0.72
=0.64+0.12
=0.76
（8/9+1/6）×72%【递等式】
=8/9×0.72+1/6×0.72
=0.64+0.12
=0.76