Final answer:
The adoption of mechanical calculators in offices changed the profession of bookkeeping by reducing the need for manual calculations and allowing businesses to hire fewer bookkeepers.
Step-by-step explanation:
The adoption of mechanical calculators in offices changed the profession of bookkeeping. Employers no longer needed as many bookkeepers to manually perform calculations because mechanical calculators were more efficient and accurate. This allowed businesses to streamline their operations and reduce costs by hiring fewer bookkeeping personnel.