I really don't think you understand what you are asking.
Are you saying that for multiplying to 32 bit integers they don't all use the same method? Well, the reason they all work is that the only methods people create machines that use is methods that work.
It's like asking "I hear there is more than one way to clean your house, if so what mathematical formula or innate ability would explain how they all recreate the phenomena of cleaning?"
Can you clarify what you are asking?
Edit: I looked at your other questions, you clearly think computers are magic or something.
People build computers. The math works because they build the computer so the math works. They build it so 1s and 0s are represented by voltages, and the computer can combine those voltages so that math happens.
There is nothing magic about voltages that make math happen. The machine was built to do math. Someone had to go "well if this component takes in a volt from A but not B it sends a volt to C. If it takes in a volt from A and B it sends a volt to D. This is how it does math. Everyone who designs a CPU needs to make sure they did it in such a way that math works. If it took in a volt from A and B and sent a volt to C instead of D then you'd get the wrong result.