Which of the following would result in the correct amount of sugar?

Given
The sugar needed is 2/3 cups.
The amount of sugar founded is 1/2 cups.
To find the estimation of the remaining sugar needed.
Explanation:
It is given that,
The needed sugar is 2/3 cups.
The sugar found is 1/2 cups.
Let x the estimated amount.
Then,
[tex]\begin{gathered} \frac{2}{3}=\frac{1}{2}+x \\ x=\frac{2}{3}-\frac{1}{2} \\ x=\frac{4-3}{6} \\ x=\frac{1}{6} \end{gathered}[/tex]Hence, the answer is 1/6.