The Romans solved one of the medium’s problems, finding a way to protect the writing on a wax tablet, making it suitable for legal documents or contracts. They drilled holes through its frame, tied it shut with a cord, and applied wax seals – up to seven, depending on the seriousness of the document.

instance, writing the number 87 in the Egyptian system would require 15 symbols: eight heels and seven vertical marks. The new Greek system would need only two symbols: π for 80, and ζ for 7. (The Roman system, which supplanted Greek numbers, was a step backward toward the less sophisticated Egyptian system. The Roman 87, LXXXVII, requires seven