作业帮9.69*9.9简便计算
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/15 17:19:38
=3.58*(10-0.1)+0.5=3.58*10-3.58*0.1+0.5=35.8-0.358+0.5=35.942
3.8*9.9+0.38=3.8*9.9+3.8*0.1=3.8*(9.9+0.1)=3.8*10=38
9.9×9.9+0.99=9.9×9.9+9.9×0.1=9.9×(9.9+0.1)=9.9×10=99
99.9×9.9=(100-0.1)*9.9=100*9.9-0.1*9.9=990-0.99=989.01
=1.36x9.9+1.36x0.1=1.36x(9.9+0.1)=1.36x10=13.6
9.9×9.9+19.9=9.9×（10-0.1）+19.9=9.9×10-9.9×0.1+19.9=99-0.99+19.9=99+18.91=117.91
=（8+0.8）*12.5*9.9=【8*12.5+0.8*12.5】*9.9=(100+10)*9.9=100*9.9+10*9.9=990+99=1089
原式=78.6-（16.7-10）+0.1=78.7-6.7=72实在不知道还能怎么简便了.
9.9×9.81=（10-0.1）×9.81=10×9.81-0.1×9.81=98.1-0.981=97.1+1-0.981=97.1+（1-0.981）=97.1+0.019=97.119
9.9+9.99+9.999=10-0.1+10-0.01+10-0.001=30-0.111=29.889
9.6+9.9*100-9.9=990-0.3=989.7
18.76*9.9+100.1=18.76*（10-0.1）+100+0.1=18.76*10-18.76*0.1+100+0.1=187.6+100+0.1-1.876=287.6-1.776=28
解题思路：化简小括号后，变为依次大1/2的等差数列。问题可求。解题过程：varSWOC={};SWOC.tip=false;try{SWOCX2.OpenFile("http://dayi.prced
41*9.9+4.1=4.1*99+4.1*1=4.1*(99+1)=4.1*100=410
8.7X9.9=8.7X(10-0.1)=8.7X10-8.7X0.1=87-0.87=86.13
"2.6×9.9=2.6×（10-0.1）=26-0.26=25.74"
4.3*（10-0.1）=4.3*10-4.3*0.1=43-0.43=42.57