作业帮23*0.01 2.3*9.9简便运算
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/04 19:39:31
（1.1+9.9）*45/2=247.5每次增加0.2,从1.1增加到9.9需要44次,总共45项,平均项5.5正好在中间所以也可以直接用5.5*45=247.5
(9.9+0.1)+(99.9+0.1)+(999.9+0.1)-0.3=10+100+1000-0-3=1110-0.3=1109.7
原式=（100+0.1）*99-9.9=100*99+0.1*99-9.9=9900
9.78-0.78+9.9=18.9
13.9×9.9＋1.39=13.9×9.9＋13.9×0.1=13.9×（9.9+0.1）=13.9×10=139
=(10-0.1)x0.81=10x0.81-0.1x0,81=8.1-0.081=8.019
9.9*5.5+0.55=9.9*5.5+5.5*0.1=(9.9+0.1)*5.5=10*5.5=55
(9.9+0.1-9.9+0.1)/0.0=(9.9-9.9+0.1+0.1)/0.01=0.2/0.01=20
楼上正解,付第二种解法6.18X9.9+0.618=6.18X(10-0.1)+0.618=61.8-0.618+0.618=61.8
0.027+9.9×0.027=0.027×（1++9.9）=0.027×（10+0.9）=0.027×10+0.027×0.9=0.27+0.0243=0.2943再问：我怎么弄不明白，，更糊涂了再
0.09+9.9×0.9=0.1×0.9+9.9×0.9=(0.1+9.9)×0.9=1×0.9=0.9
（9.9+0.1）×3.5-3.5×0.1=10×3.5-0.35=35-0.35=34.65再答：好评
0.027+9.9*0.27楼主发现其中都有27的是吧!这里0.027=0.27*0.1还明白原式=0.27*0.1+9.9*0.27同时提取0.27原式=0.27*（0.1+9.9）=0.27*10
10×3.8－0.1×3.8就好了
78×9.9＋0.78=78×(10-0.1)+0.78=780-7.8+0.78=780-(7+0.8)+0.78=c-0.8+0.78=(780-7)-(0.8-0.78)=783-0.02=78
9.9×12.6=（10-0.1）×12.6=10×12.6-0.1×12.6=126-1.26=126-（1+0.26）=126-1-0.26=125-0.26=124.74
187.6X9.9+18.76=18.76X99+18.76=18.76X（99+1）=18.76X100=1876
9.6×9.9＝9.6×（10－0.1）＝9.6×10－9.6×0.1＝96－0.96＝95.04
0.86＋8.6×9.9=8.6x0.1+8.6x9.9=8.6x(0.1+9.9)=8.6x10=86