Egyptians used only unit fractions. To represent $\frac{3}{8}$ the Egyptians would have used the fraction $\frac{1}{4}$ and $\frac{1}{8}$. Together these fractions are equivalent to the original total, but use only unit fractions to express the sum. Once students have some knowledge of fraction addition they can begin to attack these problems. My students had also covered multiplication of fractions which made the process easier. Here is the activity they did:
One process introduced in the video is the “loaf of bread method.” Many of my students understood this method and stuck with it through the activity. If an Egyptian wants to share 5 loaves of bread with eight people he will start by splitting 4 loaves into halves. Then the leftover loaf will get split into eighths. Each person will then get half a loaf and an eighth of a loaf.  $\frac{5}{8}=\frac{1}{2}+\frac{1}{8}$