Question

The numbers of times the digit $3$ will be written when listing the integers from $1$ to $1000$ is

Answer 1

$\frac{\text{3}}{\uparrow }\frac{10}{\uparrow }\frac{10}{\uparrow }+\frac{9}{}\frac{\text{3}}{\uparrow }\frac{10}{}+\frac{9}{\uparrow }\frac{10}{\uparrow }\frac{\text{3}}{\uparrow }$
$\Rightarrow 100+90+90$
$\Rightarrow 280$
$\left(\frac{}{\uparrow }\frac{10}{\uparrow }\right)+\left(\frac{9}{\uparrow }\frac{}{{\uparrow }_3}\right)\Rightarrow \text{19}$
$3\to 1$
$280+19+1=300$