简便运算答对了好评
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/07/05 14:58:28
简便运算答对了好评
![](http://img.wesiedu.com/upload/9/a0/9a075bed2017456a2af8eaa780006877.jpg)
![](http://img.wesiedu.com/upload/9/a0/9a075bed2017456a2af8eaa780006877.jpg)
![简便运算答对了好评](/uploads/image/z/16708192-16-2.jpg?t=%E7%AE%80%E4%BE%BF%E8%BF%90%E7%AE%97%E7%AD%94%E5%AF%B9%E4%BA%86%E5%A5%BD%E8%AF%84%26nbsp%3B)
1.1/2+1/4+1/8+……+1/256
=(128+64+32+16+8+4+2+1)/256
=(1+128)*8/(2*256)
=129/64
2.2/3+2/9+2/27+2/81+2/243
=2*(81+27+9+3+1)/243
=2*(81+1)*5/(2*243)
=410/243
3.9.6+99.6+999.6+9999.6+99999.6
=90000+9000*2+900*3+90*4+9*5+0.6*5
=90000+18000+2700+360+45+3
=90000+18000+2700+408
=90000+18000+3108
=90000+21108
=111108
=(128+64+32+16+8+4+2+1)/256
=(1+128)*8/(2*256)
=129/64
2.2/3+2/9+2/27+2/81+2/243
=2*(81+27+9+3+1)/243
=2*(81+1)*5/(2*243)
=410/243
3.9.6+99.6+999.6+9999.6+99999.6
=90000+9000*2+900*3+90*4+9*5+0.6*5
=90000+18000+2700+360+45+3
=90000+18000+2700+408
=90000+18000+3108
=90000+21108
=111108