Rather than Platonism (mathematical realism) I believe that numbers (and addition and subtraction and multiplication...) were developed by abstraction from earlier (physical) machinery that once existed in the real world. Cockshott, et al, (Computation and its limits, Oxford Univ. Press, 2012) describe how this may have occurred on pages 11 through about 27. Some of my experiments with Asa H explore how abstractions are formed. It's easier to follow what's going on inside Asa than it is to understand the inner workings of a neural network program. It's harder to follow what's going on inside Asa as compared to deductions in an expert system, however.
Higher order mathematical operations can then be composed out of addition, subtraction, and multiplication as is done with computers.