Find closest multiple of $20$ to $84$. We see that $4 \times 20 = 80$ is the nearest. Now subtract $80$ from $84$ to get reminder $4$. Add $4$ to quotient.
Find closest multiple of $20$ to $40$. We see that $2 \times 20 = 40$ is the nearest. Now subtract $40$ from $40$ to get reminder $0$. Add $2$ to quotient.
Since $0$ is less than $20$, stop the division. The reminder is $0$. The topmost line $042$ is the quotient. Remove all zeros at the start of the quotient to get the actual quotient $42$.
