To find the quotient of 4 divided by one-fifth, you can multiply 4 by the reciprocal of one-fifth. The reciprocal of one-fifth (1/5) is five (5).
So, you would calculate:
\[ 4 \div \frac{1}{5} = 4 \times 5 \]
Now, calculate:
\[ 4 \times 5 = 20 \]
Therefore, the answer is that you should multiply 4 by 5.