Simplify the following text for a Grade 9 native English-speaking person.
Original: Although Luca Pacioli did not invent double-entry bookkeeping , his 27-page treatise on bookkeeping contained the first known published work on that topic , and is said to have laid the foundation for double-entry bookkeeping as it is practiced today .
Simplified: Another writer from the Netherlands wrote that double-entry bookkeeping was done by the Greeks .