Interesting. From your link, it seems our modern usage of cypher stemmed from this!
The word came to Europe with Arabic numerals. From “zero,” it came to mean “any numeral” (early 15c.), then (first in French and Italian) “secret way of writing; coded message” (a sense first attested in English 1520s), because early codes often substituted numbers for letters.
About zeros, my guess would be that the ad doesn’t mean zero in the literal sense, but in the sense of how many places to shift intermediate products by during a multiplication. You’d add zeros to the right of each term, to get the power of 10 right for the intermediate products. Normally doing a hand multiplication you just don’t write those down, merely imply it with alignment. But in principle, the zeros are there, and you have to get the count of them right.
But that’s just guessing. I have never used a machine like that before!
I had to look up the term ‘ciphers’ in the context of this ad, since its usual usage is in cryptography. It turns out this is an old term for the 0 digit in Arabic numerals per https://www.physicsforums.com/threads/confused-about-ciphers-in-the-book-arithmetic-for-the-practical-man.1078238/
Interesting. From your link, it seems our modern usage of cypher stemmed from this!
About zeros, my guess would be that the ad doesn’t mean zero in the literal sense, but in the sense of how many places to shift intermediate products by during a multiplication. You’d add zeros to the right of each term, to get the power of 10 right for the intermediate products. Normally doing a hand multiplication you just don’t write those down, merely imply it with alignment. But in principle, the zeros are there, and you have to get the count of them right.
But that’s just guessing. I have never used a machine like that before!