Answer:
2/3 cups of flour
Explanation:
Lucas recipe needed 5/6 cup of flour.
Sarah's recipe needed 1/6 cup of flour.
The difference
[tex]\begin{gathered} \text{Difference}=\frac{5}{6}-\frac{1}{6} \\ =\frac{4}{6} \\ =\frac{2}{3}\text{ cups} \end{gathered}[/tex]Therefore, Lucas needed 2/3 cups more of flour.