I'm even further from getting it now. 240cm being a multiple of 12, it can be divided by 2,3,4,6 without precision loss. Also this logic around inches only work

I'm even further from getting it now. 240cm being a multiple of 12, it can be divided by 2,3,4,6 without precision loss. Also this logic around inches only works if you happen to need to divide 1 inch. It doesn't work anymore if you need to divide 1.1 inch. It actually work exactly the same in the metric system if you need to divide 1.2cm Engineering is math. You start from your constraints, and finish with an acceptable level of imprecision based on your requirements, your tools and your materials. Whatever you do it's never precision work, exactitude only exists on paper.