To solve \( \frac{1}{2} \div 4 \), you can rewrite the division as multiplication by the reciprocal:
\[ \frac{1}{2} \div 4 = \frac{1}{2} \times \frac{1}{4} \]
Now, multiply the fractions:
\[ \frac{1 \times 1}{2 \times 4} = \frac{1}{8} \]
Thus,
\[ \frac{1}{2} \div 4 = \frac{1}{8} \]
Therefore, \( 1/2 \div 4 = 1/_________ \) leads to the answer:
\[ \frac{1}{8} \]
So the blank should be filled with 8.