Find the remaining money after buying cards, then find the fraction of the original spent on food.<br><br>
&bull; Spent \( \frac{1}{4} \) on cards → remaining = \( 1 - \frac{1}{4} = \frac{3}{4} \)<br>
&bull; Spent \( \frac{2}{3} \) of the remaining on food = \( \frac{2}{3} \times \frac{3}{4} \)<br>
&bull; \( \frac{2}{3} \times \frac{3}{4} = \frac{6}{12} = \frac{1}{2} \)<br><br>
Final Answer: \( \frac{1}{2} \)