Question

Solve mentally$.$

$100,00,000-72,19,258$

Answer 1

Given numerical expression is $100,00,000-72,19,258$

Replace every zero from the left with $9$ and the last zero with a $10$

$$\begin{gathered} 10000000 \\ \underbrace{|}\underbrace{|}\underbrace{|}\underbrace{|}\underbrace{|}\underbrace{|}\underbrace{|} \\ 99999910 \end{gathered}$$

Now subtract each digit from $9$ and last digit from $10$

$$\begin{gathered} 99999910 \\ -7219258 \\ \overline{2780742} \end{gathered}$$

Hence$,$ the value of $100,00,000-72,19,258$ is $27,80,742$