0.61*0.25+0.18*1/4+0.21*百分之二十五简便计算

0.61*0.25+0.18*1/4+0.21*百分之二十五
=0.61*0.25+0.18*0.25+0.21*0.25
=0.25*(0.61+0.18+0.21)
接下来自己算,很容易的

0.25*(0.61+0.18+0.21)
=0.25*(0.61+0.39)
=0.25
0.25=1/4=25%

0.61×0.25＋0.18×1/4＋0.21×25%
＝0.61×0.25＋0.18×0.25＋0.21×0.25
＝（0.61＋0.18＋0.21）×0.25
＝1×0.25
＝0.25