$$ \begin{matrix} 9 & 8 & 3 & 5 & 6 \\ 7 & \dot{0} & \dot{4} & \dot{6} & 7 \end{matrix} \\ \_\_\_\_\_\_\_\_\_\_\_\_\_ \\ 2 \quad 7 \quad 8 \quad 8 \quad 9 \\ \_\_\_\_\_\_\_\_\_\_\_\_\_ $$
Steps :
$$ \therefore\ 7 $$ cannot be subtracted from $$6$$
So add completed digit $$3$$ of $$7$$ to $$6$$ and write in total along with mark an Ekadhik on previous digit $$6$$ of $$7$$.
Thus, complete the subtraction process.