Let's start by determining how much of the sandwich Bishop had left after lunch.
Bishop ate \( \frac{1}{2} \) of the sandwich for lunch. This means the amount she had left is:
\[ 1 - \frac{1}{2} = \frac{1}{2} \]
Next, after work, she ate \( \frac{2}{3} \) of the remaining sandwich. The remaining amount is \( \frac{1}{2} \).
To find out how much she ate after work, we calculate \( \frac{2}{3} \) of \( \frac{1}{2} \):
\[ \text{Amount eaten after work} = \frac{2}{3} \times \frac{1}{2} = \frac{2 \times 1}{3 \times 2} = \frac{2}{6} = \frac{1}{3} \]
Therefore, Bishop ate \( \frac{1}{3} \) of the sandwich after work.