İt depends on how number is defined. Euclid defined number as multitude of units. Zero does not have units so zero is not a number and cannot enter arithmetic operations such addition and subtraction. (Division is repeated subtraction.) For the same reason one was not a number in Euclid.

I’m trying to find out when did Euclid lose his authority. By 1901, Bertrand Russell was defining number as an abstract relation, namely, as a one-to-one relation between two sets.