简便运算:0.61×0.25+0.81×1/4+0.21×25%....错了，是0.18

简便运算:0.61×0.25+0.81×1/4+0.21×25%....错了，是0.18
简便运算:0.61×0.25+0.81×1/4+0.21×25%
....错了，是0.18

简便运算:0.61×0.25+0.81×1/4+0.21×25%....错了，是0.18
0.61×0.25+0.18×1/4+0.21×25%
=（0.61+0.18+0.21）×0.25
=1×0.25
=1

0.61×0.25+0.81×1/4+0.21×25%
=(0.61+0.81+0.21)×25%
=1.63/4
=0.4075

0.61×0.25+0.81×1/4+0.21×25%
=0.61X0.25+0.81x0.25+0.21x0.25
=(0.61+0.81+0.21)x0.25
=1.63x0.25
=0.4075