1.135+3.346+5.557+7.768+9.979=?9.8+99.8+999.8+9999.8+99999.8

一、 1.135+3.346+5.557+7.768+9.979 =1.135+9.979+3.346+7.768+5.557 =11.114+11.114+5.557 =27.785 二、 9.8+99.8+999.8+9999.8+99999.8 =5*9.8+(90+900+9000+90000) =49+99990 =39+100000 =100039 三、 6.11+9.22+8.33+7.44+5.55+4.56+3.67+2.78+1.89 =(6.11+1.89)+(9.22+2.78)+(8.33+3.67)+(7.44+4.56)+5.55 =8+12+12+12+5.55 =44+5.55 =49.55 四、 1.996+19.97+199.8 =(2-0.004)+(20-0.03)+(200-.0.2) =222-(0.004+0.03+0.2) =222-0.234 =221.786 五、 1.1+3.3+5.5+7.7+9.9+11.11+13.13+15.15+17.17+19.19 =(1.1+9.9)+(3.3+7.7)+5.5+(11.11+19.19)+(13.13+17.17)+15.15 =11+11+5.5+30.3+30.3+15.15 =27.5+75.75 =103.25