Đặt $a=404,610086:0,405015=\dfrac{404610086}{405015}$
$b=82380,071:81,003=\dfrac{82380071}{81003}$
Ta có: $a=\dfrac{999.405015+101}{405015}=999\dfrac{101}{405015}$
$b=\dfrac{1017.81003+20}{81003}=1017\dfrac{20}{81003}$
$\Rightarrow C=a+b=999\dfrac{101}{405015}+1017\dfrac{20}{81003}$
$C=\left(999+1017\right)+\left(\dfrac{101}{405015}+\dfrac{20}{81003}\right)$
$C=2016+\left(\dfrac{101}{405015}+\dfrac{100}{405015}\right)$
$C=2016+\dfrac{201}{405015}=2016\dfrac{1}{2015}$
Vậy $C=2016\dfrac{1}{2015}$