Find closest multiple of $12$ to $15$. We see that $1 \times 12 = 12$ is the nearest. Now subtract $12$ from $15$ to get reminder $3$. Add $1$ to quotient.
Find closest multiple of $12$ to $30$. We see that $2 \times 12 = 24$ is the nearest. Now subtract $24$ from $30$ to get reminder $6$. Add $2$ to quotient.
Since $6$ is less than $12$, stop the division. The reminder is $6$. The topmost line $012$ is the quotient. Remove all zeros at the start of the quotient to get the actual quotient $12$.
