In the Rhind Papyrus (RMP) we have 8 + 2/3 + 1/10 + 1/2190. A four-digit concluding denominator allows for some fairly hefty modern-day fractions, even when keeping the expression to the sum of four unit fractions. And, after all, the pi fraction 256/81 can be expressed as 3 + 1/9 + 1/27 + 1/81.
It might also be useful to know that the AEs had a decimal notation.
You might also point out that 5+1/2 is not the only seked - this is a general term for slope. The Chephren seked is 5+1/4.
I agree that Rossi is a good read, but almost any book on the Rhind Mathematical Papyrus would be a good start for anyone needing to express their work the Egyptian way and to understand their mathematical procedures and capabilities.