“0.666×0.7×0.222×0.9”应该是“0.666×0.7+0.222×0.9”吧,否则无法简算0.666×0.7+0.222×0.9=（0.222×3）×0.7+0.222×0.9=0.222×（3×0.7）+0.222×0.9=0.222×2.1+0.222×0.9=0.222×（2.1+0.9）=0.222×...