Find closest multiple of $23$ to $39$. We see that $1 \times 23 = 23$ is the nearest. Now subtract $23$ from $39$ to get reminder $16$. Add $1$ to quotient.
Find closest multiple of $23$ to $168$. We see that $7 \times 23 = 161$ is the nearest. Now subtract $161$ from $168$ to get reminder $7$. Add $7$ to quotient.
Since $7$ is less than $23$, stop the division. The reminder is $7$. The topmost line $017$ is the quotient. Remove all zeros at the start of the quotient to get the actual quotient $17$.