For readers interested in the history of calculators and computing, including mechanical, electromechanical, and electronic, once again I recommend a recent book:
K Houston, Empire of the Sum: The rise and reign of the pocket calculator, Norton 2023.
Especially, see chapters 4-6 about digital mechanical devices, which typically were decimal rather than binary in construction and interface.
Later chapters concentrate on electronic devices, including an important British product, the Amita, which used a combination of a Dekatron, thyratrons, and Nixie tubes in a package reminiscent of the electromechanical comptometers that preceded it.
The book does not cover mainframes, etc., but concentrates on calculators.
For the history of digital representation of numbers, the standard reference is U C Merzbach and C B Boyer, A History of Mathematics, 3rd ed, Wiley 2011.
Both books are free of claptrap.