Remember, 'integrated' meant initially just 'more than one component'. It would start with poster-sized wiring diagrams, switch elements, photosensitive spots etc. As it got smaller and more circuit elements were added the math may have progressed with it.

It's more than the math. It requires modern understanding of electromagnetism and material science accounting for semiconductors. From that things like practical electric motors/generators and plethora other technologies become essentially a corollary.