查看完整版本: 求教巧算，谢谢！

求教巧算，谢谢！

2.89×47＋1.53－1.4×1.1＋24×0.11＋288×0.53－0.1＝.

2.89×47＋1.53－1.4×1.1＋24×0.11＋288×0.53－0.1
=289×0.47+1.53-14×0.11+24×0.11+288×0.53－0.1
=(288+1)×0.47+1.53+(24-14)×0.11+288×0.53－0.1
=288×0.47+1×0.47+1.53+10×0.11+288×0.53－0.1
=288×(0.47+0.53)+(0.47+1.53)+(1.1-0.1)
=288×1+2+1
=288+2+1
=291.

[em11]
    2.89×47＋1.53－1.4×1.1＋24×0.11＋288×0.53－0.1
＝28.9x4.7+1.53-1.4x1.1+2.4x1.1+28.8x5.3-0.1
=28.8x4.7+0.1x4.7+28.8x5.3+1.53+1x1.1-0.1
=288+0.47+1.53+1.1-0.1
=288+2+1
=291

[[i] 本帖最后由 小小小青龙 于 2009-6-15 15:27 编辑 [/i]].

2.88*47+0.47+1.53-1.4*1.1+2.4*1.1+2.88*53-0.1
=2.88*(47+53)+2+1.1*(2.4-1.4)-0.1
=2.88*100+2+1.1-0.1
=288+2+1
=291.

感谢ＬＳ各位，厉害！.

2.89*47+1+0.53-1.4*1.1+2.4*1.1*288*0.53-0.1
=2.89*47+289*0.53+1.1+1-0.1
=289*0.47+289*0.53+2
=289+2
=291.

一看就是小学四年级，现在的内容实在是难啊.

啊，这是四年级的题啊，介难啊。.

五年级的.

有个疑问,除了2.89×47和288×0.53两项以外,其它的有必要巧算么?
×11的口算算法,已经属于巧算范畴,还是不算?
有老师在么?.